idle issues and sudden bucks!! please help

[96darkhorse]

ok..im several issues. it idles around 500-1000rpm, it keeps on jump up in between, whether its hot or cold....now, when im driving the car seems different(slugish) like if its not getting enough air. sometimes when im driving, the car suddenly bucks, as if teh throttle closed for a second and suddently opened up again.... i cleaned my MAF , throttel body, and IAC(not completely though)...now what could be wrong?

 

[HazMat404]

thats a lot of timing for our cars. anything more than 15*-16* is a waste. usually 13*-14* is best for more cars. is there a puff of smoke that comes out when it surges or does it smell like gas at all?? make sure everything is plugged in. sounds stupid but many times i think something is wrong but a plug sorta wiggled loose. also check your air filter (im sure you did cause you cleaned all that other stuff) but a dirty filter can make ur car run horrible. ill try to think of other stuff but thats the simple stuff along with a few questions for now

 

[revhead347]

Your idle speed controller has gone bad, change it. They have a history of problems.

Kurt

 

[94TURBO5 O]

Sounds like a firing issue to me Check your wires, plugs and dist rotor. If your wire has melted somewhere on the header then it could be arcing off metal thus causing a bucking. It could also be a fuel pump or filter. Injectors could also be clogged as well. There are many things that could cause these motors to run funky but yet there is also a solution to each one and you'll find answer here for sure.
Good luck!

 

[ShiftTheDrift]

Your idle speed controller has gone bad, change it. They have a history of problems.

Kurt

This might sound dumb, but I'm fighting some major idle problems and looking for anything at this point.
So, is this the same thing as an IAC?

 

[mytight95]

yes its the same, might want to check the tfi module, the coil, and even replace the pickup in the dist.


jason

 

[JJ95GTID]

dead spot in the throttle position sensor (TPS)?

 

[Silver85TC]

How old are your ECT and IAT sensor's? If these are original/old, they could definitely be causing your roving idle/bukcing issues.

Cheers

 

[CivicEater]

The ECT? How does the Engine cooalnt temp sensor affect bucking and such?

 

[mo_dingo]

IAC valve only controls the amount of air getting to the engine when the butterfly is closed. It wouldn't make the car run rough, for any reason. When mine broke, my idle speed was steady at 2200 rpm's.

Timing is irrelavant, unless somehow it's different than 18*. Check it anyway. The dizzy bolt may have came loose or something stupid like that. I would run it at 13-14 though. You are LOSING performance with that much timing added.

He said the idle speed problem was exactly the same no matter if the car was hot or cold. That rules the ECT out. A bad ECT would make the car run richer than hell, and trigger a CEL.

Speaking of CEL, have you ran the codes yet? What came up?

The TPS function is to tell the computer when you go to WOT (open or closed loop opertaion). Anything else inbetween is irrelevant. You can check the voltage if you like. It's really a waste of time though.

So when the car is bone cold, or completely warmed up, the idle problem remains the same, correct? If so, that rules out the O2 sensors.

Have you performed any work to the car within the last 2 weeks? If so, what was it, and did the problem start immediately afterwards?

#1 - Run the codes - report back here for diagnosis.

#2 - If no codes are present, check the connections to all main engine sensors & ensure proper connection (MAF/IAT/IAC/TPS/O2/ECT).

#3 - Check timing.

#4 - Remove and note the condition of all 8 spark plugs individually.

#5 - Hook up a vacuum gauge & check vacuum. Same for Fuel Pressure.

That's it for now. Let us know what happens.
Scott

 

[revhead347]

I've known three cars to have the same symtoms above; poor idle, and sudden bucking, including my own car. Every time it was the IAC. I would recommend changing that first. The IACs are known to have problems on 94-95s. The worst that could happen is that you have to return the IAC.

Kurt

 

[revhead347]

This might sound dumb, but I'm fighting some major idle problems and looking for anything at this point.
So, is this the same thing as an IAC?

It might be. If you experience sudden bucking when you are driving it's a dead give away of an IAC failure.

Kurt

 

[96s281]

It might be. If you experience sudden bucking when you are driving it's a dead give away of an IAC failure.

Kurt

Hey revhead, do you know something that we don't about the IAC? I thought it only functioned when the throttle is closed? How could it cause problems when the throttle is open?

 

[ShiftTheDrift]

It might be. If you experience sudden bucking when you are driving it's a dead give away of an IAC failure.

Kurt

Man, there seems to be a lot of us having these problems! In my case, the car drives okay.. It's just that it won't idle anything less than 1200rpms and after a guy can spend 8 hours, get heat stroke tweaking idle to 900rpms only to have the following problems:

1) When you turn the car off, it's is like trying to start a lawn mower.

2) Afterwards getting it started, it won't idle at 900rpms and immediately starts idle hunting, then dies

3) You cannot start the car without having your foot on the gas or it's guaranteed to die.

4) The idle sticking happens no matter what at like 2000rpms when coming to a rolling stop for example, then sloooooooooowly comes back down.

5) The one that pisses me off the most, in all my findings of how to properly set idle, there's no way on God's Green Earth this car will idle with 1 1/2 turns on the stop plate screw and the IAC disconnected.

Hence, you have to give the throttle plate screw like "6" turns before it will stay running, but all 4 problems still remain present.

Please, don't even get me started on trying to run accessories.. ::evil laugh::

I've been fighting this for 2 1/2 weeks and have gotten no where. I've been so tempted just to take out a loan or something and replace the TB, TPS, IAC, EGR, MAF, and so on! I mean...I just don't know.

 

[96s281]

Man, there seems to be a lot of us having these problems! In my case, the car drives okay.. It's just that it won't idle anything less than 1200rpms and after a guy can spend 8 hours and get heat stroke tweaking idle to 900rpms, then the following symptoms occur:

1) When you turn the car off, it's is like trying to start a lawn mower.

2) Afterwards getting it started, it won't idle at 900rpms and immediately starts idle hunting, then dies

3) You cannot start the car without having your foot on the gas or it's guaranteed to die.

4) The idle sticking happens no matter what at like 2000rpms when coming to a rolling stop for example, then sloooooooooowly comes back down.

5) The one that pisses me off the most, in all my findings of how to properly set idle, there's no way on God's Green Earth this car will idle with 1 1/2 turns on the stop plate screw and the IAC disconnected.

Hence, you have to give the throttle plate screw like "6" turns before it will stay running, but all 4 problems still remain present.

I've been fighting this for 2 1/2 weeks and have gotten no where. I've been so tempted just to take out a loan or something and replace the TB, TPS, IAC, EGR, MAF, and so on! I mean...I just don't know.

Hey Shift, I had the same problem with my startup last year and put a new IAC on and no problems after that. My problem now is both a rough idle and misfire while driving. I've done some searches and it appears it could be a bad 02 sensor but I'm not sure either.

 

[ShiftTheDrift]

Yeah, I removed the IAC and cleaned it with carb cleaner and it ended up having no affect.

I hooked up with a buddy yesterday and he's mailing me a new IAC.

If it were a bad O2, wouldn't it throw a check engine?

 

[96s281]

Yeah, I removed the IAC and cleaned it with carb cleaner and it ended up having no affect.

I hooked up with a buddy yesterday and he's mailing me a new IAC.

If it were a bad O2, wouldn't it throw a check engine?

As far as a check engine light, I'm in the process of finding that out. From what I hear, bad 02 sensors don't necessarily throw a code but I might just say F it and get a new one anyway. They're like $60-80 and I might have to take that chance.

 

[ShiftTheDrift]

Yeah, lemme know what you find out if in fact a bad O2 would throw a code?

Good luck!

 

[96s281]

Yeah, lemme know what you find out if in fact a bad O2 would throw a code?

Good luck!

I hope I'll have an answer for ya, but more importantly for myself

 

[stng94]

I would check the voltage at the TPS. I had this problem last year and had to replace my TPS.