Sputtering Accelerator Pedal

[Dbiz]

So lately, and by lately I mean for about the last month or so, the truck has had this issue with a sort of sputtering or gagging gas pedal when I accelerate. It's more of cringe or gag, or sputter as I press the accelerator down, most often felt when I'm going uphill or particularly when I'm on an interchange ramp that slant's upward on a freeway. The truck still manages to fight through it and continue to accelerate but I can't shake the feeling that something may be wrong with the engine. I'm wondering whether or not just tightening the nuts on the throttle response connections under the hood will solve the problem and that is going to be my first attempt to solve the issue. However, just thought I'd throw it out there and see if anyone has had a similiar problem or if anyone knows a way to fix it. Any suggestions would be appreciated.

 

[SkidPalace]

What have you done in terms of a standard tune up?
The symptoms you describe are very ambiguous, but any kind of hesitation will be the result of an out of tune engine, and very unlikely related to the gas pedal. Of course you can remove the slack from the gas pedal linkage at the throttle body, but that won't cause a stutter or "cringe" whatever that means.
Could be basic maintenance, plugs/wires, air filter, pcv, MAf, A/F or O2 sensors and so forth. Give us your service history and more info on your rig (miles, engine type etc, any CELs) and we can go from there.

 

[Mr. Leary]

Second the the above. Check all that stuff. Remove your intake tube and inspect the throttle body. If the main valve in there is gummed up, it could cause the hesitation.

Petrol engines pump air and add gas. If it is sputtering a bit, that means there is either too much gas added or too much air flow. I know this is very ambiguous, but it helps to go about solving the problem thinking about it that way.

It sputters with sudden acceleration. So when you increase the air flow by opening the throttle, it is either adding too much air or not adding enough fuel. Since adding too little fuel is unlikely without throwing a code, you should focus on what happens on the intake side of things. Inspect the air intake leading up to the engine for leaks and take a good look at the MAF sensor. Next check your vacuum lines, as these are also a possible cause of the engine acting normally except when under heavy acceleration. A leaking or disconnected vacuum line will allow too much air to be added to the intake after the MAF sensor but before the O2 sensor can compensate.

If the computer was not as smart as it is (Toyota), you would likely have an idle problem as well, but they adjust for stuff like that so fast that you may never notice.

Hope this helps.

 

[Mr. Leary]

So lately, and by lately I mean for about the last month or so, the truck has had this issue with a sort of sputtering or gagging gas pedal when I accelerate. It's more of cringe or gag, or sputter as I press the accelerator down, most often felt when I'm going uphill or particularly when I'm on an interchange ramp that slant's upward on a freeway. The truck still manages to fight through it and continue to accelerate but I can't shake the feeling that something may be wrong with the engine. I'm wondering whether or not just tightening the nuts on the throttle response connections under the hood will solve the problem and that is going to be my first attempt to solve the issue. However, just thought I'd throw it out there and see if anyone has had a similiar problem or if anyone knows a way to fix it. Any suggestions would be appreciated.

While I doubt tightening the bolts will hurt anything, I doubt it will help anything. You would be more likely to have problems while letting off of the accelerator if that were the case.

Forgot to ask... is this a prolonged problem, or just when you hit the accelerator?

Meaning under heavy load in general or during a rapid acceleration...

 

[Dbiz]

Thanks for the input guys. I'm actually starting to think it might either be bad spark plugs, or a cylinder that's not firing. I'm really hoping its the former and not the latter, but I got a bad feeling its the cylinder. The truck will idle a little funny sometimes while sitting at a stoplight and the shudder usually occurs when at higher speeds, (40 MPH +) and when going uphill or on the freeway where more power would be needed. While this shudder does occur often, it only occurs when my foot is on the gas pedal. If I push the pedal down harder when this occurs the engine will usually work through it and give me more power but I still think it's probably a bad cylinder as it's just the other 5 working harder to give me the power.

I'm planning on going to see about new spark plugs today and try that first. If not I think I might have to look into getting a cylinder replaced.

Just FYI, it's a '96 SR5, V6 automatic trans with about 173,000 miles on it. Service history is good. Regular oil changes and maintenance performed, although it's due for an oil change now. Only issues I've ever had with it are the rear axle seals but that's it.

Anyone think I'm on the right track or maybe barking up the wrong tree here?

 

[brian2sun]

I'm planning on going to see about new spark plugs today and try that first. If not I think I might have to look into getting a cylinder replaced.

Well, you can't replace a cylinder because they are bored out of the hunk of steel that is your engine block. Many things can cause a cylinder to miss and a bad spark plug/wire is one of the most common causes. You're supposed to replace plugs/wires every 24K. And use dual-electrode NGK or Denso plugs ONLY!!!

Start there and and let us know how it goes. Also keep an eye on your coolant level and make sure you're not loosing any over the next couple weeks.

 

[SkidPalace]

Go ahead and change the plugs and wires, they are due anyway, but before you do that, pick the low hanging fruit by cleaning your TB and MAF, also run some Sea Foam through the vac lines and replace your PCV.
These are all cheap and easy DIY tune ups. Do the Sea Foam before you change the plugs, since loosening all that crud from your intake system has been said to muck up your plugs. I'm not 100% sure I believe that, but seeing as you are installing plugs anyway, you may as well do it in that order.

 

[SkidPalace]

By the way, if you were having a cylinder misfire you should be getting a check engine light.

 

[jsmarine]

I agree, you should be geting a CEL for a misfire. Correct me if i am wrong but your 96 is OBD2 right? For some reason I cant remember if it was 95 or 96 when they changed to OBD2. Anyways, if you suspect a misfire, then yes check the spark plugs and wires and dont forget the coils too. I had a coil go bad on mine before. And go with Denso!

 

[brian2sun]

By the way, if you were having a cylinder misfire you should be getting a check engine light.

You are right, but a partial or intermittent miss doesn't always set of the CEL. I had a miss for a full year and only got a CEL maybe once a month, but drove it everyday. When it wasn't throwing a code, there was no doubt it was still missing on just about every start up and also randomly when driving. I did all the normal tune-up/maintenance 1st, then cleaned the MAF, TB, IAC, etc.. and after that stuff didn't help, I went to a diagnostician and we figured it out together over a few days. It turned out to be dirty valves and after doing a machine-based induction cleaning (Motorac), I've finally got it running perfect! The cleaning also increased my mpgs by about 60% (I went from about 10 to 16!!!) and it's been getting that consistenly ever since.

Still do the simple recommended stuff first, but keep this cleaning in mind because it's a very good thing to do anyways just to keep your engine tip top. Here's my writeup:
http://www.toyota-4runner.org/3rd-g...ning-horrible-but-not-any-more-hopefully.html

 

[004Gunner]

The CEL will not always come on during misfires. If the misfires are sporadic enough you will not get a code. I've seen my vehicle have over a dozen misfires in 30 seconds while idling and not throw the code. That's the nice thing about having live data when doing diagnostics.

 

[Dbiz]

Thanks for all the help guys. Definitely way more feedback than I expected. I ended up going down to my local Autozone and talking to those guys about my problems for a little bit, and then wen't down to a mechanic after that and talked with him about it. On my way down to the mechanic, however, my check engine light did come on finally. After all the consultations I ended going and buying some RGK plugs and brought the truck home to install them.

I finished replacing the spark plugs this morning, after going thoroughly cleaning out the air intake/box and lines. Didn't realize how much of a ***** the driver's side plugs were to get to, but I managed to get er done. After a test drive the truck seems to be running normally. I did varying types of acclerations to see if the problem would come back, including gunning it up to freeway speed but so far it's running smoothly again. On the flipside, the check engine light is still on. I'm thinking I might just take it in an have a diognostic run just to make sure that everything is running correctly and to see what is triggering the check engine light. Hopefully I fixed the problem though and won't have any more issues. We'll see.

PS: JsMarine, '96 was the year they switched to OBD2 so that's what mine has. I'm not sure if one of the plugs was intermitently bad and that's why light didn't come on right away. However, as it came on eventually, The bad plug could have been the result of the misfire and eventually making the CEL come on. I'm just not sure why it's still on now if the engine is running normally. Maybe it'll turn off after a few days. Who knows.

 

[96Blacklimited]

Thanks for all the help guys. Definitely way more feedback than I expected. I ended up going down to my local Autozone and talking to those guys about my problems for a little bit, and then wen't down to a mechanic after that and talked with him about it. On my way down to the mechanic, however, my check engine light did come on finally. After all the consultations I ended going and buying some RGK plugs and brought the truck home to install them.

I finished replacing the spark plugs this morning, after going thoroughly cleaning out the air intake/box and lines. Didn't realize how much of a ***** the driver's side plugs were to get to, but I managed to get er done. After a test drive the truck seems to be running normally. I did varying types of acclerations to see if the problem would come back, including gunning it up to freeway speed but so far it's running smoothly again. On the flipside, the check engine light is still on. I'm thinking I might just take it in an have a diognostic run just to make sure that everything is running correctly and to see what is triggering the check engine light. Hopefully I fixed the problem though and won't have any more issues. We'll see.

PS: JsMarine, '96 was the year they switched to OBD2 so that's what mine has. I'm not sure if one of the plugs was intermitently bad and that's why light didn't come on right away. However, as it came on eventually, The bad plug could have been the result of the misfire and eventually making the CEL come on. I'm just not sure why it's still on now if the engine is running normally. Maybe it'll turn off after a few days. Who knows.

Hey, i was following your post, and noticed we had the same problem, esp when going up an incline and accelerating over 40mph. I would have chimed in, but all the guys here were giving you the right information. My check engine took a few day to come on as well. Mine did go out though after i replace the plugs and wires. Not assuming that you are stupid or nothing, but did you disconnected you positive terminal from you battery? If you did not do that before installation then your computer did not get a chance to reset. but still check her out though

 

[brian2sun]

Yeah, if you pull either of the cables off the battery for 30-40 min it will reset the ECU and turn the CEL off. I would do this (if for nothing else) just to see if the CEL gets triggered again because right now you don't know if it's still throwing the code or if it just hasn't reset yet.

 

[Dbiz]

Actually, believe it or not, my CEL went off last night when I was driving back home so I guess(and hope) everything is back to normal and it was just a simple issue of changing out the plugs. I'll definitely keep an eye on it for a while but I'm just glad it wasn't anything worse. But thanks again for the input and help guys. Much appreciated.

 

[egebo]

I have a similar problem andToyota service doesn't want the aggravation of diagnostic w/o a code. 1999 4 runner, v6, 4wd, stuttering when maintaining constant speed above 50mph. Doesn't happen when accelerating. It through the maf code a month ago so I cleaned it and reset the code. It hasn't thrown the code again. I started having the stuttering problem so I replaced the fuel filter (aftermarket) and ran three tanks of injector cleaner (Lucas) and just replace the spark plugs (NKG). Still stutters. Toyota tech thought it might be misfiring but couldn't diagnose it with out it throwing a code. It does not reproduce this stuttering action when in neutral at similar rpms (2200). Any thoughts?

 

[Sukirman]

I am also interested here. I sometimes feel the truck sort of "shudder" or "hesitate", usually when going up an incline and with the engine running at or slightly below 2000 RPM. It sorta feels like the tranny can't decide on what gear to use (maintain current gear or downshift).

I have had the truck ('01 V6 Limited 2WD with 148k mi) for a little less than 3months (I'm 3rd owner as far as I can tell). All I did maintenance wise were oil and oil filter changes, new air cleaner element and fuel injector cleaner 4k miles ago. ATF drain and fill is scheduled next month and also radiator flush and new set of tires. After reading this thread, I think I will also do spark plugs and coils next. Practically no maintenance record from the previous (2nd) owner save for the oil changes and new a battery installed late last year. Original owner was pretty meticulous, taking the truck to a dealership in Frisco, TX for scheduled maintenance, including TB and water pump service at 90k miles.

 

[lightingcslt]

accelorator body

does anyone out there know where I can purchase this without having to go
to Toyota they want 800.00 for this part any help would be apprieciated. its for
a 2002 Toyota 4runner 3.2 6 cylinder 2 wheel drive

 

[Darkyoda727]

Yup, it continues

I replaced the water pump and radiator. I went through putting the timing belt back on two or three times until it ran seemed ok in park i can press pedal in park or neutral. Still seems sluggish till I put it in gear and press on the gaspedal. Bogs down may flog out idk javent gone that far. if I just touch the gas pedal it will slowly gain speed if I press it bogs down. I've replaced wires plugs rotor&cap many vacuum lines maf sensor another Puck like one on the passenger side little orange vaccum thing + other parts not motor related... It ran alot better before i replaced water pump n radiator. What did i do?
Ill check plugs n wires. Any ideas? Thanks 4Runner nation.

 

[Darkyoda727]

Timing seems ok runs ok starts kinda sluggish but idles good. I need to replace booster cylinder n maybe slave as well which one do yo guys think is first. Fluid makes it brake pedal will hiss to floor. Booster?