Gas pedal to the floor, doesn’t want to downshift

[ir0nma1den]

I’ve had this issue for a year or so. When I’m on long drives with lots of climbing, I notice sometimes my 4runner refuses to shift into a lower gear despite pressing the gas pedal all the way to the floor. I’ll have to manually shift the transmission into second for it to drop. I just got back from a miserable drive from Denver to the mountains and I began to have this issue. Now when after dropping it down in second manually a few times, I noticed that the next time I did it, nothing happened - it didn’t actually drop into second. I’m not sure if this is a fuel pump/filter issue or something to do with the transmission. It has 200k miles on it and I replaced the transmission that the PO pink milk shaked. I know these 4runners don’t exactly have a lot of power, but getting no power with the pedal to the floor is concerning. It works fine 90% of the time even on long drives.

Not sure if this is related as I haven’t had to deal with this recently, but sometimes after long drives in the summer I’d go park for a bit and come back to my engine not turning over when I go start the truck. After waiting a bit it would work. Last time I researched this issue, it seems that the one way fuel valve in the fuel line may be the culprit. Not sure if this is part of the problem with my truck refusing to accelerate under the conditions described above.

 

[mtbtim]

Check the transmission kickdown cable and make sure it doesn't have excessive slack. You can adjust the slack out of it using the two nuts that affix the cable to the throttle body. You don't want the cable taught, but just a slight amount of slack.

 

[Skulking]

Check the transmission kickdown cable and make sure it doesn't have excessive slack. You can adjust the slack out of it using the two nuts that affix the cable to the throttle body. You don't want the cable taught, but just a slight amount of slack.

The kickdown cable may be a problem, but given that using the shift lever to shift into 2nd also wasn't shifting the transmission, I'd lean towards a transmission issue. Possibly in addition to other problems, but I'd try to resolve the shifting issue before messing with anything else.

When was the last time the transmission fluid was changed? I assume you have checked for codes? Also, not really related to the problem, but is there a reason you are trying to shift all the way down to 2nd rather than just turning off OD and putting it in 3rd?

 

[diverscale]

Look at the trans fluid level while hot (20 min drive) and on park.

Can you hook up a obd2 with a data reader, and see if your throttle position sensor records the % of opening correctly? Also, does the truck has its full power when you are finally on second gear and WOT, or is it sluggish? The kick down cable is for hydraulic pressure and I don't think it will change your shift pattern.

These trucks are pretty simple and probably only use % throttle opening and RPM for it to control up and down shifts.

 

[gamefreakgc]

Check the kickdown cable on the top of the throttle body. It's the one with the little knob in the cable and is on the right hand side on the top. It can be installed incorrectly after a repair where there's too much slack.

 

[mtbtim]

The kickdown cable may be a problem, but given that using the shift lever to shift into 2nd also wasn't shifting the transmission, I'd lean towards a transmission issue. Possibly in addition to other problems, but I'd try to resolve the shifting issue before messing with anything else.

When was the last time the transmission fluid was changed? I assume you have checked for codes? Also, not really related to the problem, but is there a reason you are trying to shift all the way down to 2nd rather than just turning off OD and putting it in 3rd?

You're right. I missed that about 2nd gear.

 

[ir0nma1den]

Check the transmission kickdown cable and make sure it doesn't have excessive slack. You can adjust the slack out of it using the two nuts that affix the cable to the throttle body. You don't want the cable taught, but just a slight amount of slack.

This is what my kickdown cable looks like. Doesn’t seem to be the problem here.

The kickdown cable may be a problem, but given that using the shift lever to shift into 2nd also wasn't shifting the transmission, I'd lean towards a transmission issue. Possibly in addition to other problems, but I'd try to resolve the shifting issue before messing with anything else.

When was the last time the transmission fluid was changed? I assume you have checked for codes? Also, not really related to the problem, but is there a reason you are trying to shift all the way down to 2nd rather than just turning off OD and putting it in 3rd?

Trans fluid was changed in 2017 at 162k miles. No codes. Guess I just forget about the OD button.

Check the kickdown cable on the top of the throttle body. It's the one with the little knob in the cable and is on the right hand side on the top. It can be installed incorrectly after a repair where there's too much slack.

If anything my accel cable is a bit stretched and has some slack but from the pic above the kickdown cable looks ok.

Anyone know a reputable shop in/around Denver?

 

[19963.4lsr5]

I’ve found on my 96 and both 97’s that there are certain instances where it only drops 1 gear instead of two.

I also am of the impression that the down shifting is a product of the TPS and RPM and not the “throttle valve cable”/“line pressure”. We have a solenoid for gear selection and there is no way for the PCM to monitor the line pressure, plus the line pressure and the TPS would basically track each other.

IMO…….


Sent from my iPhone using Tapatalk

 

[Organ]

Might be the relay

 

[Bad Luck]

What everyone is calling the "kickdown cable" only controls line pressure in the transmission. The transmission is electronically controlled and does not monitor the line pressure control cable at all.

 

[Bad Luck]

Might be the relay

What relay?

 

[spartacus]

I’ve had this issue for a year or so. When I’m on long drives with lots of climbing, I notice sometimes my 4runner refuses to shift into a lower gear despite pressing the gas pedal all the way to the floor. I’ll have to manually shift the transmission into second for it to drop. I just got back from a miserable drive from Denver to the mountains and I began to have this issue. Now when after dropping it down in second manually a few times, I noticed that the next time I did it, nothing happened - it didn’t actually drop into second. I’m not sure if this is a fuel pump/filter issue or something to do with the transmission. It has 200k miles on it and I replaced the transmission that the PO pink milk shaked. I know these 4runners don’t exactly have a lot of power, but getting no power with the pedal to the floor is concerning. It works fine 90% of the time even on long drives.

Not sure if this is related as I haven’t had to deal with this recently, but sometimes after long drives in the summer I’d go park for a bit and come back to my engine not turning over when I go start the truck. After waiting a bit it would work. Last time I researched this issue, it seems that the one way fuel valve in the fuel line may be the culprit. Not sure if this is part of the problem with my truck refusing to accelerate under the conditions described above.

I've had the same happen. Going up I-70 west it helps to have the OD off for it to down shift into 2nd when you step on it.. Sometimes releasing the gas pedal and pushing it back in works. There is a lag on steep inclines at 50mph and up. The ecm dosent let the transmission down shift at that speed for some reason. Combine that with altitude and you get tremendous power loss. specially when you get slowed down by traffic on the long inclines.The only remedy that works for me is to stay in the left lane and go fast.
edit: As fast as you can safely go.

 

[gamefreakgc]

Hmm, there's something else at play then. My 98 downshifts just fine on the pass on I-80 (0 to 7200 ft elevation) but the transmission was replaced before I bought it so maybe it's a bit more fresh. I'm not sure what shop can do without any Check Engine Lights other than throwing parts at it that may or may not work.

 

[jross20]

Ah welcome to my world... I've been trying to figure out this loss of power thing for months now... And now, and the last 6 months my gas mileage has totally gone down the drain... From 19-19.5 now down to 16-16.5.

Driving through the mountains I have the same exact problem, there's a large zone on the gas pedal where no matter how much further I push it literally nothing happens. And I'm not just talking about the fact that it doesn't shift, I mean the sound of the engine doesn't change at all. Normally you can tell when it might be going the same speed but pushing harder but I mean I can literally just push the pedal from what feels like 50% to 100% and it just literally makes no difference at all...

If anybody can figure this out I would be glad... I've been wondering if it might be the catalytic converter... Some folks suggested taking out the front O2 sensor to see if it helps. I wanted to do this but I've noticed that if I were to do so there's no heat shield on the opposite end of the opening which seems bad?

Maybe it doesn't matter?

So anyway, op I feel your pain. Truck is nearly undrivable in the mountains. I've even been passed by another third gen that was towing a trailer uphill and there was absolutely nothing I could do to keep up with him. I mean he eventually got out of sight because it was just impossible lol

 

[brillo_76]

Hmm... I am wondering what your compression psi are? On my 1998 I wouldn't shift down to the floor. I just tighten the shift down cable by about 1/8 to 1/4 tighter then it's original position. Fixed my issue. As I think the cable slowly stretch.

If your loosing mpg and power. I am thinking possible fuel injectors not clean. Lower compression caused by valves needing adjusted.

As if your head gaskets are good and your not loosing psi through the head gaskets. These engines are not noted for rings going bad. Leaves head gaskets, injectors and valves out of adjustment as possibilities.

If the compression psi is testing out decent it would rule out head gasket especially if you did a leak down test.

I wouldn't expect spark plugs and wires as that mostly shows up as misfire issues.

If all is checking out good. I verify you pcv valve isn't stuck.

I think by observing other users these engines really should have their valves adjusted before 300k miles. Or at least verified the valves are all in spec around 300k miles.

If our valves are not opening fully and closing properly, I could definitely see the mpg going down and major power loss occurring.

These are just thoughts of possibilities of what could be issues. Naturally, it maybe something totally different.



Sent from my SM-A505U using Tapatalk

 

[Romeo1]

Before you do anything else, verify that the air filter is good and not clogged. Verify that the throttle cable is adjusted properly and opening the throttlebody to 100%. If not fix throttle cable or replace until you do get throttlebody to open all the way.

Then check spark plugs, if they have more than 25,000 miles replace. If the gap is excessive also replace. Replace them with the correct ones and nothing but the correct ones, Wires also. Go by the Toyota ones as the wires already come with the right clips in the right spots.

Compression test hot and cold while you’re there with the throttle open and all the plugs removed. Is there any deviation in the numbers from cylinder to cylinder and hot cold that’s out of spec? If there is check valve clearances and or cylinder leak down.

You very well could have a transmission problem. Until you verify that the engine is running like it supposed to you’re wasting your time in my opinion.

My 99 had miserable drivability initially due to previous owner neglect. New plugs, wires, and and an adjusted throttle body to the correct position created roughly an 87% improvement. So much so that I had to readjust the transmission kickdown cable as the shifts were way too firm.

Check plugs and compression, don’t assume it’s good. Also swap out the transmission fluid it has been a while. Once those are done then you can begin chasing transmission issues.

 

[ir0nma1den]

I've had the same happen. Going up I-70 west it helps to have the OD off for it to down shift into 2nd when you step on it.. Sometimes releasing the gas pedal and pushing it back in works. There is a lag on steep inclines at 50mph and up. The ecm dosent let the transmission down shift at that speed for some reason. Combine that with altitude and you get tremendous power loss. specially when you get slowed down by traffic on the long inclines.The only remedy that works for me is to stay in the left lane and go fast.
edit: As fast as you can safely go.

Ah welcome to my world... I've been trying to figure out this loss of power thing for months now... And now, and the last 6 months my gas mileage has totally gone down the drain... From 19-19.5 now down to 16-16.5.

Driving through the mountains I have the same exact problem, there's a large zone on the gas pedal where no matter how much further I push it literally nothing happens. And I'm not just talking about the fact that it doesn't shift, I mean the sound of the engine doesn't change at all. Normally you can tell when it might be going the same speed but pushing harder but I mean I can literally just push the pedal from what feels like 50% to 100% and it just literally makes no difference at all...

If anybody can figure this out I would be glad... I've been wondering if it might be the catalytic converter... Some folks suggested taking out the front O2 sensor to see if it helps. I wanted to do this but I've noticed that if I were to do so there's no heat shield on the opposite end of the opening which seems bad?

Maybe it doesn't matter?

So anyway, op I feel your pain. Truck is nearly undrivable in the mountains. I've even been passed by another third gen that was towing a trailer uphill and there was absolutely nothing I could do to keep up with him. I mean he eventually got out of sight because it was just impossible lol

Both of you have my same problem. Pressing the pedal to floor doesn't change RPMs or the noise the engine should be making when you are trying to accelerate.

Your comment about the O2 sensors are interesting since I've been chasing a P0420 issue for about 2 years. Have replaced both front and rear sensors and still have the CEL light on. My exhaust actually split in half between the 1st and 2nd cat when I was driving to the beach and was laying on the frame cross member's due to rust. Had a shop weld it back in place and they defitnely missed a spot because I hear a slight hiss that sounds like gas escaping through a hole between the weld. Maybe installing that computer mod that spoofs the O2 readings would do the trick.

Hmm... I am wondering what your compression psi are? On my 1998 I wouldn't shift down to the floor. I just tighten the shift down cable by about 1/8 to 1/4 tighter then it's original position. Fixed my issue. As I think the cable slowly stretch.

If your loosing mpg and power. I am thinking possible fuel injectors not clean. Lower compression caused by valves needing adjusted.

As if your head gaskets are good and your not loosing psi through the head gaskets. These engines are not noted for rings going bad. Leaves head gaskets, injectors and valves out of adjustment as possibilities.

If the compression psi is testing out decent it would rule out head gasket especially if you did a leak down test.

I wouldn't expect spark plugs and wires as that mostly shows up as misfire issues.

If all is checking out good. I verify you pcv valve isn't stuck.

I think by observing other users these engines really should have their valves adjusted before 300k miles. Or at least verified the valves are all in spec around 300k miles.

If our valves are not opening fully and closing properly, I could definitely see the mpg going down and major power loss occurring.

These are just thoughts of possibilities of what could be issues. Naturally, it maybe something totally different.



Sent from my SM-A505U using Tapatalk

Before you do anything else, verify that the air filter is good and not clogged. Verify that the throttle cable is adjusted properly and opening the throttlebody to 100%. If not fix throttle cable or replace until you do get throttlebody to open all the way.

Then check spark plugs, if they have more than 25,000 miles replace. If the gap is excessive also replace. Replace them with the correct ones and nothing but the correct ones, Wires also. Go by the Toyota ones as the wires already come with the right clips in the right spots.

Compression test hot and cold while you’re there with the throttle open and all the plugs removed. Is there any deviation in the numbers from cylinder to cylinder and hot cold that’s out of spec? If there is check valve clearances and or cylinder leak down.

You very well could have a transmission problem. Until you verify that the engine is running like it supposed to you’re wasting your time in my opinion.

My 99 had miserable drivability initially due to previous owner neglect. New plugs, wires, and and an adjusted throttle body to the correct position created roughly an 87% improvement. So much so that I had to readjust the transmission kickdown cable as the shifts were way too firm.

Check plugs and compression, don’t assume it’s good. Also swap out the transmission fluid it has been a while. Once those are done then you can begin chasing transmission issues.

Air filter was replaced at 176k. Spark plugs at 171k. I'll take it to a shop for a compression test.

 

[Bad Luck]

Both of you have my same problem. Pressing the pedal to floor doesn't change RPMs or the noise the engine should be making when you are trying to accelerate.

Your comment about the O2 sensors are interesting since I've been chasing a P0420 issue for about 2 years. Have replaced both front and rear sensors and still have the CEL light on. My exhaust actually split in half between the 1st and 2nd cat when I was driving to the beach and was laying on the frame cross member's due to rust. Had a shop weld it back in place and they defitnely missed a spot because I hear a slight hiss that sounds like gas escaping through a hole between the weld. Maybe installing that computer mod that spoofs the O2 readings would do the trick.






Air filter was replaced at 176k. Spark plugs at 171k. I'll take it to a shop for a compression test.

The oxygen sensor simulator you are talking about is only for the rear oxygen sensor. Rear oxygen sensor is strictly for monitoring catalytic converter efficiency. Any exhaust leaks before or shortly after that sensor will affect its readings.

 

[Romeo1]

Both of you have my same problem. Pressing the pedal to floor doesn't change RPMs or the noise the engine should be making when you are trying to accelerate.

Your comment about the O2 sensors are interesting since I've been chasing a P0420 issue for about 2 years. Have replaced both front and rear sensors and still have the CEL light on. My exhaust actually split in half between the 1st and 2nd cat when I was driving to the beach and was laying on the frame cross member's due to rust. Had a shop weld it back in place and they defitnely missed a spot because I hear a slight hiss that sounds like gas escaping through a hole between the weld. Maybe installing that computer mod that spoofs the O2 readings would do the trick.






Air filter was replaced at 176k. Spark plugs at 171k. I'll take it to a shop for a compression test.

Your due for another set of plugs.That’s an every 30k thing. You need to swap tranny oil also. Lastly the air filter. That’s a long time on an air filter….. seriously. They’re 16$. Takes 20 seconds to change……

If you do any amount of of road, your way past due.

I helped to clean out an air filter on a 99’ powerstroke about 20 years ago. It wouldn’t even do 55 mph on the interstate. The owner, a guy who I really looked up to at the time, kept cussing it. Damn governor…… yada yada. I finally said let’s check the filter minder. Pulled all the way up. Banged out the air filter on the off-ramp. Left a hilariously large pile of dirt. Boom, power restored. 75 mph uphills with ease then.

All in trying to say it’s that pulling the well I changed this at X miles doesn’t mean anything. You Could have a nest full of leaves and garbage in front of the air box from rodents for all you know. Go verify, mileage doesn’t mean squat.

 

[gamefreakgc]

Both of you have my same problem. Pressing the pedal to floor doesn't change RPMs or the noise the engine should be making when you are trying to accelerate.

Your comment about the O2 sensors are interesting since I've been chasing a P0420 issue for about 2 years. Have replaced both front and rear sensors and still have the CEL light on. My exhaust actually split in half between the 1st and 2nd cat when I was driving to the beach and was laying on the frame cross member's due to rust. Had a shop weld it back in place and they defitnely missed a spot because I hear a slight hiss that sounds like gas escaping through a hole between the weld. Maybe installing that computer mod that spoofs the O2 readings would do the trick.






Air filter was replaced at 176k. Spark plugs at 171k. I'll take it to a shop for a compression test.

The P0420 will kill your gas mileage and power, pretty much every Check Engine Light will. It's seeing air in the exhaust and trying to tune it out. Have a shop weld it up or replace the offending section and power should start to come back.