robingb

Help! I have made 2 visits to a very well respected and knowledgable P mechanic but still have a problem. I thought I would get the boards input before going back for a 3rd visit.

Sometimes but not always, my idle oscillates betw 100 and 250 rpms . All the while, my oil pressure gauge seems to oscillates even more. Indeed, sometimes the tach is constant but the oil pressure still oscilates. On occasion , car will stall when I come to a quick stop. The idle stabilizer valve was cleaned. The O2 sensor was replaced. An electrical connection with the A/C system was fixed. Nevertheless, I still have the oscillating idle most of the time. Help! Thanks, Gary

Rocket Rob

Does the problem occur both with or without the AC on? And do you have a lightweight flywheel?

robingb

it does occur w and w/o a/c although i think a bit more w a/c. as a recent owner of car, i don't know about light weight flywheel. my p mechanic also had same question.

altarchsa

If not LW flywheel, my next guesses would be:

1. An intermittent air leak in the intake system

2. Intermittent spark from a bad coil.

A idle speed with low oil pressure, the pressure could change dramatically with a very minor change in the speed, whci could explain why you're thinking the oil pressure is fluctuating with no change in speed.

afast16v

Idle control microswitch??? I had a similar situation with my 94 964 and turned out to be a microswitch not closing the loop therefore ECU thought the throtle was still partially open and it would cause an erratic idle and even make it die.

Duck

+1 - I had the same problem with the idle control microswitch.