cold high idle issue

[vortecfcar]

Hey guys, I just registered here. Long time member on a couple other car sites thirdgen.org/LS1tech.com.

 

anyway, I've gone throught the FAQ's and searched around here and the best I've been able to come up with on my high idle (cold) is that I might have an IAC sticking or going out. I have the next week off and plan on getting this car ready for the winter (just bought it). Are there any troubleshooting things I should know about.

 

thanks for any insight, nice site you guys got here.

 

Nick

 

ps- this is a fun little car, hopefully it runs decent for a few months!

[vortecfcar]

no dice huh, Ill report back sunday.

[birdman]

tps could be the problem and i would check the vac lines

[z34Phoenix]

also the DOHC's have problems with the intake manifold gaskets they could be leaking. with 155K i would check:

 

-intake manifold gaskets upper and lower.

-timing belt. when was it done and does it need it my guess is yes.

-if oil in spark plug holes, i would do valve cover gaskets too

-O2 sensor

-TPS sensor? not sure if the pre 96 have these.

-IAC

[GOT2B GM]

Definately take a look at the Intake Manifold and Plenum gaskets, as they are a common issue with these motors. Check for vacuum leaks as the plastic vacuum lines get brittle with age. Clean/replace IAC Valve if needed.

 

I had a problem on my car with the Power Steering pressure switch being stuck on, constantly telling the ECM to increase engine rpm, but thats not too common.

[GOT2B GM]

-TPS sensor? not sure if the pre 96 have these.

 

All EFI motors have these don't they?

 

If you mean MAF sensor, 91-93 don't have them, they use a "speed density" system.

[3pt1lumina]

TPS on my dad's 3100 Lumina 112k just went... same problems as you described. Went about a week then threw an SES code... changed it and now the car runs like tits!

[birdman]

i know the line to the vac ball comes undone quite often, easy fix if thats it

[vortecfcar]

thanks for the relies guys, so far I took the IAC out and cleaned it/ lubed it to no avail. I have my fingers crossed that the timing belt doesnt go out while I own this thing. I pulled the belt cover off and the belt looked to be in good shape. I do have oil in the spark plug holes - ugh. I dont really want to go crazy on this thing, just enough maintainance to last the winter if you know what I mean.

 

Ill pull the TPS tomorrow and check it out. Any chance of cleaning it up? Ill check for vac leaks on the intake too. Although I would suspect a continuous high idle in this scenerio.

 

Can I get more info on this power steering pressure switch? My power steering is noisey and I think the pump had a leak at one time (oil slung under the hood near power steering pump).

 

Stay tuned.

[vortecfcar]

well, put a TPS in it. No help. Next day, car wouldnt start. Now it starts and runs but idles at 3000RPM. :shock: :shock:

 

anybody want to come buy this money pit for 500 buck before I drive it into the owners house.

[Prospeeder]

sounds like a big vacuum leak, did u change the Upper intake manifold gaskets, if they go bad, it creaks a HUGE vacuum leak and then make it idle really high

[vortecfcar]

Prospeeder, you rock!

 

problem solved.

[Prospeeder]

haha good to know i helped ya out!