I apologize if this has been asked a million times, I did a quick browse through the forums and couldn't find complete confirmation for what I am about to ask. My car (( 1992 Camaro rs, 305 TBI )) surges while idling in park, RPMs consistently go up and down from about 1000 to 10,000 but doesn't stall out. When I put it in gear the RPMs go to around 5000. It hesitates a little during acceleration but not all the time and its not bad at all, when the speed is up it drives just fine. It stalled out twice, first time I was pulling off my drive way, which is sloped, while backing down off it my foot was on the break and it stalled when I got into the street, cranked it right back up and drove it to work with no problems. Second time I was pulling into my drive way, put foot on the brake as I was getting close to the garage door and it stalled out. This morning, after it sitting all night, I started it and it only idled at 5-6000 rpms, instead of around 15,000 then idling down like usual. So later on I popped the hood disconnected the IAC connector, started the car and it idled at around 12.000 rpm in park... Put it in gears and it idled at around 6-8000 rpms. So then I went back and plugged in the IAC connector, started the car and it went back to idling around 5000 in park, and almost stalling every time I put it in gear. So is this a direct indicator that the IAC valve needs to be replaced or cleaned, I haven't removed the valve to actually look at it yet.? Or can it still be any amount of other problems.? And help is greatly appreciated.

 

First, I'm guessing (hoping) that your numbers are off by an order of magnitude. Normal idle in gear, engine hot, should be about 550-600 RPM, not 5,000-6,000. That applies to the rest of the numbers as well.

Second, if you haven't already done so, the throttle body, idle air passages, and IAC should be cleaned. Even a new IAC isn't going to work in a dirty TB or with varnish in the air passages.

There are a few pictorial threads showing how to remove the IAC pintle and spring, clean and lube the unit, and reassemble and install it.

When finished, the throttle minimum air position should be checked/set, the TPS position/voltage should be verified (closed throttle minimum on a '92), then the IAC can be relied upon to do its job.

Use the SEARCH feature to find "IAC cleaning" or "throttle minimum air" to begin with.

 

Yeah my fault I added an extra "0" at the end of each of the rpm numbers. My mistake. And thanks I'm going to look up those threads and go from there, if I have any extra questions I'll ask.

 

After searching the threads for about 45 minutes I couldn't find anything detailed about cleaning the IAC valve, couldn't find any pictorials either. There was 998 results so I was just picking posts based off their titles, if anyone can provide me with a link to a good thread explaining in detail how to clean the IAC valve that would help greatly. What I know is to have carb / throttle body cleaner and to hold the IAC valve pointing down when spraying it, so I don't ruin it. Can some one tell me what tools I need to remove it.? And after removing the IAC valve do I spray into the direct passage that it came out of or through another passage on the TB.? Also I've seen that some ppl say to just reconnect it and others say you have to connect it to certain torque specifications.?

 

Also, I just seen this wasn't connected and reconnected it. would that affect anything.?

 

Only if you want to use the cruise control.

 

Try reading over this thread:

https://www.thirdgen.org/forums/post...702-post5.html

 

Ok I removed the IAC valve and cleaned everything. I noticed there wasn't a gasket when I removed it, and auto zone and o Reilly's websites don't even have a gasket for the IAC valve.? What's up with that, is there supposed to be a gasket or is that only on certain ones.? But I'm putting everything back together and Imma see what happens.

 

Need a gasket to help prevent vac leaks

 

Couldn't find the gasket so I just bout a new IAC valve... Now when I start my car on a cold start it will idle at around 700 rpm and then go up to around 1200 rpm and idle back down. And keep going up and down. So I drove it around the block to get the cars temperature up, and after that it idles perfectly (( when the car is warm )) in all gears. But when I go from park/neutral to drive or reverse the RPMs drop to about 100 then goes up to about 5-600. Any ideas what's causing this .?