Dark Blue

Hi, my '89 S4 Auto w 92k mi has started stalling when warm. Idle is low and car just quits but will restart. I tried the WD40 trick on the idle stabilizer through T junction, but that didn't seem to help. Any suggestions on what to look at next.

Car is on Nantucket and sat all winter. Any suggestions on a good 928 wrench anywhere nearby. If I can't fix it I suspect this will be a real PITA.

Thanks everyone!

Zirconocene

There are lot of things to check, but I will offer my personal experience from when my car was doing similar things: Check your fuel pressure (the pressure itself), the regulator, and your dampers. Getting those sorted is what fixed a similar issue on my car.

Good luck

Speedtoys

Like..its runs slower and slower as it warms up?

When was the last time you checked thrust bearing play?

mdkelly1

You asked for a good wrench nearby (Nantucket). Worf is in the Boston area, but assuming you need someone within Ferry distance of Nantucket, you might call Scott McNamara at "Sports Imports of Cape Cod" in Falmouth, MA. He serviced my 928 for nine years while I was on Cape Cod. He's the owner (and also a former 944 racer) who knows and understands the transaxle cars, and he's easy to do business with. It was a while ago, but I see that he's still there. His lead mechanic at the time was Jerry and he could sort out anything on a 928. His number is 508-563-3848. Here is a link for reference: https://www.pcarshops.com/massachuse...no-falmouth-ma

Petza914

Based on my experience with our 89 944 S2 which has similar controls (both my 928s are older 16v versions), check the hoses that run to and from the ISV and also replace the coolant temp sensor. That sensor tells the car when the engine is warm to change the fueling - sounds like yours may never be changing it and why it works when cold but gets progressively worse as it gets warrm.

Mrmerlin

Please follow Speedtoys suggestion first.
Flex plate check/ crank end play clearance check.

NOTE Quick check pull the dipstick,
drip the oil onto a black piece of cardboard ,
then look at the oil in the sun,
if you see lots of metal ,
dont run the engine till the flex plate bolt is loosened.

soontobered84

I would think that a key would be that it restarts. Could there be a floating obstruction in the fuel tank that works it's way to block the fuel line. Your 89 should have an internal fuel pump (if it hasn't been removed in the past) The internal pump has a short hose that deteriorates. The blockage could be there if you determine it's a fuel issue.

Check flex plate/crank end play first, though.

Good luck!

Dark Blue

Thanks for all of the helpful suggestions! Hoping it's not a flex plate issue. Flex plate was supposedly checked by RVM in Atlanta a few years ago, but if any of you know him you know how that goes. I'll take a look at oil per Mr. Merlin's suggestion this weekend and post back. Thanks again!

Steve

Mrmerlin

in the mean time dont run the engine till the flex plate check has been performed

Geo1965

Μy - 89S4 acted the same, turned out to be an overtighten throttle cable not allowing the idle switch to close properly... took literally years to figure it out and took 5 mins to adjust.

George