cleaned iac, now having idle problem

[bkmonster]

Hi,
I just got done cleaning the IAC in my '93 sho. Initially, it had a surging idle (when I would come up to a stop light), but after the IAC was cleaned, this problem seemed for the most part to go away. Now, the problem I am having is that while driving, if I press in the clutch, the engine rpms drop, and the car dies. What could this be?

*side notes
-The "black paint" on the iac gasket seemed to be flaking, and I did not get it completely scraped off
-The vacumm line that attaches near the IAC is starting to show some signs of cracking

Thanks for the help!

 

[Mr Anonymous]

I'd start by checking the codes in case it's something obvious. You might also want to run the KOER tests to make sure the IAC can control idle within the PCM's limits.

Links in my sig. in case you need to learn how.

 

[sdpatt]

Try resetting the idle speed.

 

[projectSHO89]

If resetting the idle speed does not solve the problem, replace the IAC. It is responsible for maintaining idle and is likely either being mis-controlled or is defective.

Steve

 

[bkmonster]

I replaced the iac, but it really didnt help too much. Now it switched back to the original surging idle. What else could this be (The check enging light is giving me the KOER codes of 116,114,172,136,225).

 

[bkmonster]

Oh yeah, by the way

Would this have anything to do with my temperature gauge not going up, and getting poor heat from the vents. I have not got around to doing my thermostat yet.

 

[wood_e]

Ignore the 114 is it was below 50 degrees out.

136 - Oxygen sensor not switching/system lean Left or Front HO2S

172 - Oxygen sensor not switching - system is or was lean - Single Right or Rear HO2S

You seem to either have bad 02s or a lean condition...

 

[bkmonster]

so those o2 sensors could be the problem of my surging idle?

 

[oh_SHO]

I would get to the t-stat soon. The computer changes things according to temp so if your engine never reaches operating temp it could contribute to problems. Just my .02

 

[RJ-92]

bkmonster:
so those o2 sensors could be the problem of my surging idle?

Yes, very much so. What did you use to clean the IAB? I used a cleaner on mine that wasn't O2 friendly a few years back and roasted my O2 sensors. The symptoms were quite similar to what you're experiencing with this.

 

[bkmonster]

For cleaning the IAB, I used 3M Throttle Plate and Intake cleaner. I would guess that it would be o2 safe, but I guess that I will check to make sure though. I suppose that I will replace the oxygen sensors next (the ones on there have 115k on them anyway).