I've got an 88 n/a that I use as a winter beater, for the last 8-12months it developed a random intermittent surge at idle. Sometimes it's very minor on start up and goes away as soon as I bring the rpms up a bit and two or three times has been so bad it gives me driveability issues.
I pulled my maf and IAC and cleaned it all out and did a visual inspection for any air leaks after the MAF and the condition still continues. I can squeeze that large vacuum hose that runs from the intak to the TB and stall the car out. I would assume its the IAC except that it comes down from higher rpm's smoothly, but will then surge once it's settled around 7-800 rpm. Sometimes when it's really bad I can shut the car off and start it right back up and it will idle perfect for the rest of the drive or for a month. I can't put together any common circumstances that it happens such as when the engine is cold or hot or only at start up etc.
Instead of dropping a couple hundred bucks on a new IAC, I figured I'd see if anyone has any other guesses.
I pulled my maf and IAC and cleaned it all out and did a visual inspection for any air leaks after the MAF and the condition still continues. I can squeeze that large vacuum hose that runs from the intak to the TB and stall the car out. I would assume its the IAC except that it comes down from higher rpm's smoothly, but will then surge once it's settled around 7-800 rpm. Sometimes when it's really bad I can shut the car off and start it right back up and it will idle perfect for the rest of the drive or for a month. I can't put together any common circumstances that it happens such as when the engine is cold or hot or only at start up etc.
Instead of dropping a couple hundred bucks on a new IAC, I figured I'd see if anyone has any other guesses.