Hesitation driving me crazy!!!

[Skrimz]

So I am having an issue I can’t track down. Hopefully you all are smarter then I. I have a 1998 4runner V6, manual tranny. Recently it has had a “hesitation” when driving. I can be driving down the road, everything seems to be running fine, I accelerate and I get a hesitations in the engine, but then it may or may not stop if it pushes through it. But is not a consistent issue. Some days worse some days not too bad. There is no engine light on at all. I was thinking something to do with the TPS or throttle body but not sure that is it. Also thought timing belt but in my experience it would be more consistent and not a sometimes yes or sometimes no issue. Any ideas? Let me know if you need more info.

 

[JohnsD90]

So I am having an issue I can’t track down. Hopefully you all are smarter then I. I have a 1998 4runner V6, manual tranny. Recently it has had a “hesitation” when driving. I can be driving down the road, everything seems to be running fine, I accelerate and I get a hesitations in the engine, but then it may or may not stop if it pushes through it. But is not a consistent issue. Some days worse some days not too bad. There is no engine light on at all. I was thinking something to do with the TPS or throttle body but not sure that is it. Also thought timing belt but in my experience it would be more consistent and not a sometimes yes or sometimes no issue. Any ideas? Let me know if you need more info.

You know what a slipping clutch feels like? If you dont then thats probably your problem.

 

[awdjunkies]

Sometimes hesitations are fuel/spark related, when was the last maintenance? Also, like JohnsD90 says, if your rpms rise and the 4runner isn't moving any faster? could be time to replace the clutch.

 

[RS Dude]

When was the last time you changed the fuel filter?:fro:

 

[Skrimz]

yeah I know what a slipping clutch feels like. I thought about that but i have had a few clutches go out to teach me. it doesn't feel like that. I am getting pretty good engage and disengage on the clutch in all gears. Also the RPM's don't bounce around at all during the hesitation. Usually when a clutch slip happens you will see them jump I believe.

well some more info I did try and replace the fuel filter about a month ago, that was a disaster, got the wrong part, so had to throw the old one back on and wait. I don't know if that was when the hesitation started or not, can't remember for sure but might have been sometime after that. I did change it recently with one I picked up at toyota, it might have helped for a few days (or it might have been wishful thinking) but that was short lived. spark plugs changed this past summer, all was running well after that, never had a issue that quickly with spark plugs, think it could still be that?

 

[awdjunkies]

yeah I know what a slipping clutch feels like. I thought about that but i have had a few clutches go out to teach me. it doesn't feel like that. I am getting pretty good engage and disengage on the clutch in all gears. Also the RPM's don't bounce around at all during the hesitation. Usually when a clutch slip happens you will see them jump I believe.

well some more info I did try and replace the fuel filter about a month ago, that was a disaster, got the wrong part, so had to throw the old one back on and wait. I don't know if that was when the hesitation started or not, can't remember for sure but might have been sometime after that. I did change it recently with one I picked up at toyota, it might have helped for a few days (or it might have been wishful thinking) but that was short lived. spark plugs changed this past summer, all was running well after that, never had a issue that quickly with spark plugs, think it could still be that?

More info is needed:
What type of plugs? what type of gas do you use? is it the same gas station each and every time ? When you replaced the plugs, did you also replace wires?

 

[Skrimz]

More info is needed:
What type of plugs? what type of gas do you use? is it the same gas station each and every time ? When you replaced the plugs, did you also replace wires?

What type of plugs?
not 100% sure but maby NKG
what type of gas do you use?
Regular
is it the same gas station each and every time?
Nope, several different stations
When you replaced the plugs, did you also replace wires?
not this time, I thin the wires are about 1 year to 1.5 years old.

also tried running a fuel system cleaner through it when I changed the fuel filter, once again, can't be sure if it helped or not. I can try again, going up to the mountains later this week.

 

[awdjunkies]

Have you ever used Seafoam or thought about using it in your 4runner?



<iframe width="420" height="315" src="http://www.youtube.com/embed/RshzQ-YH6Jg" frameborder="0" allowfullscreen></iframe>

 

[Skrimz]

Have you ever used Seafoam or thought about using it in your 4runner?




never heard of the stuff. i used b-12 fuel system cleaner, they look different. I always wonder how well those thanks actually work...

 

[Skrimz]

Update: listened to engine and its like a really light "puffing" sound, same at exhaust. no smoke, unusual smell or anything....

 

[denverunner]

It could be a number of different things.... I would suggest checking a few things before throwing parts at it.

1. check your plugs.
A. Make SURE you are using dual ground electrode (either NGK or DENSO)
B. Check the torque on the plugs. Sounds dumb, but the recommended 14'lb isnt even enough to crush the crush washer. One of mine worked itself loose a long long time ago and caused similar hesitation symptoms.

If you're still having trouble.......

2. check your plug wires.
A. test the resistance using a DVOM.

 

[Skrimz]

It could be a number of different things.... I would suggest checking a few things before throwing parts at it.

1. check your plugs.
A. Make SURE you are using dual ground electrode (either NGK or DENSO)
B. Check the torque on the plugs. Sounds dumb, but the recommended 14'lb isnt even enough to crush the crush washer. One of mine worked itself loose a long long time ago and caused similar hesitation symptoms.

If you're still having trouble.......

2. check your plug wires.
A. test the resistance using a DVOM.

Well I have started down this path. I changed all the plugs last night. they were the single instead of dual. A friend and i are checking the wires tonight, there was one pulling against the intake valve so maby that caused an issue. it sounds like usually the TPS throws a code, not sure about the PCV yet though.

Also I was talking to a guy here. he said he has seem something similar and it was the coil pack. started doing some research and it sounds like a high possibility. one symptom was a blinking fuel light even when you have a full tank of gas, which I have experienced.
that brings me to my next question, as usual a web search gives you 100 ways to test a coil pack but does anyone have a way that actually works? what do I need to test it?

 

[awdjunkies]

Well I have started down this path. I changed all the plugs last night. they were the single instead of dual. A friend and i are checking the wires tonight, there was one pulling against the intake valve so maby that caused an issue. it sounds like usually the TPS throws a code, not sure about the PCV yet though.

Also I was talking to a guy here. he said he has seem something similar and it was the coil pack. started doing some research and it sounds like a high possibility. one symptom was a blinking fuel light even when you have a full tank of gas, which I have experienced.
that brings me to my next question, as usual a web search gives you 100 ways to test a coil pack but does anyone have a way that actually works? what do I need to test it?

Easiest ways is to swap them while the engine is running. You'll know/hear the difference.

 

[denverunner]

(inside the FSM) Checkout page 5 of 5 on the following link

http://www.ncttora.com/fsm/1996/SIL.../02rmsour/2002/024runne/ig5vzfe/ignsy/ovi.pdf

page 5 will show you how to test the resistance of the coil packs using a DVOM and page 2 (i think) shows you how to test your wires.

to test the resistance of the line you need a digital volt-ohm meter. If you're hurtin for cash, you can buy a poopy one at harbor freight for like.... what, 0.99cents? :lol:

I bought one from radio shack cuz it seemed to be the better choice and it was around $20.

To test the coil pack, position the DVOM leads as instructed on page 5. Think of it as testing a battery. One wire goes on the (+) side, the other goes on the (-) side. If the number displayed on the DVOM falls drastically outside of specs, then replace it. When testing resistance, I will repeat the test several times just be sure that I'm not getting whacky feedback. If you see the same number (or relatively the same number) post on the DVOM more than once, then that is a good indication that your doing it right.


one more thing.... IF you do end up testing the resistance on each of the coil packs, another indication that one might be bad is if you get readings of like 0.85ohms 0.85ohms and then one reads like 2.25ohms. When one is not like the other two, then it's probably bad. If all three checkout within spec, then your coils are likely not the culprit.

 

[Diagram14]

When I first got mine there was a fair amount of throttle hesitation. Ended up being a Dirty MAF. Pulled it out and shot some brake cleaner up it. I could see the grime built up on the diodes (if thats what they're called) and a quick blast of the non-chlorinated stuff got be back to resposive throttle land.