X-Jester

Greetings,

Ongoing problem since I purchased the car with a high idle following a cold start.. Just replaced my opti last night, assuming this high idle might have been related to my other ignition problems my bad opti was causing. Nothing doing, still have a high idle on cold start. My car idles between 1700 and 2000 rpm for the first 3 or 4 minutes after starting up when the engine's cool. If you take first up to about 1700, and shift into 2nd, it'll actually pull the car forward before you even apply gas. Makes me wonder what that could be, I'm thinkg I have a dirty IAC. Still, after driving for a bit, it hops right back down to normal. What kind of things could cause this? I assumed a faulty IAC would present idle problems throughout the entire drive. I also know my EGR is messed up, but I thought that only mattered when the engine was hot and you had been cruising between 1500-2000 rpms for a few minutes... I'm guessing it's a sensor somewhere, so where should I start? I hope I've given enough information for you to make an educated guess.

Thanks for your time!
Bryan

dnz28

Take your IAC off hit it with some cleaner and your car will run better than you when you purchased it.

X-Jester

Thanks, so it's in the IAC? Anyone else have recommendations?

Compstall

Your car is perfectly normal. ALL cars do this on a cold start, and it is intended to get the vehicle up to normal operating temperature quickly; has to do with vehicle emissions.

It doesn't hurt to clean out the IAC and throttlebody out once a year or so either.

scoobysnax83

ding ding ding.....

X-Jester

Thanks for your replies. My mind's put to ease. I've built up this paranoia about my car because a good few things have gone wrong with it all at once here. But, it looks like we're nearing the end of restoration and moving on to upgrades. The SLP 2OTL is getting nearer and nearer, I can't wait :P I had a '01 GT rev their flowmasters and 4.sucks at me, and I quickly put them in their place. Only my bleeder valve on my water pump vibrated loose and I started blowing smoke from under my hood, and then I just looked ridiculous. All fixed now though.

Thanks for your patience, and more importantly thanks for all of the guidance you've all given me to get my car running as good as it is now.

LT1 =

94 CAMRO Z28

I had the problem with my car bogging down and almost stalling, and then the rpms shooting back up whenever I came to an abrupt stop. Cleaned the IAC and wow, what a difference!

Aaron

Injuneer

Yes, there is a "fast idle" programmed into the PCM when the engine is cold, but it doens't set the idle at 1700-2000rpm. Here's the idle vs. coolant temp for a stock M6 program:

-40degF *** 1,200rpm
-19degF *** 1,050rpm
+3degF **** 1,050rpm
+24degF *** 1,000rpm
+48degF *** 900rpm
+89degF *** 900rpm
+111degF and above *** 800rpm

So... "normal at cold start" doesn't explain the magnitude of your problem. Check the TPS voltage at startup. Check the IAC counts at startup, and follow them as the coolant warms up.

Might give you insight into the problem.

I saw a sign once... "Just because you are paranoid, it doens't mean they aren't out to get you."

X-Jester

Thanks, I'm looking for someone locally to help me scan all those points and show me the ropes. I'll definitely keep that in mind.

Thanks for your help. I agree with what the sign says, too