Problems with '88 924s Please Help!
 

I've posted on this issue before but there have been some new developments. The re-occuring problem with this cas has been a flashing oil pressure light coupled with erratic guage movement and difficulties starting the car once it has been up to operating temperature.

Recently the car began running rough above 4000rpm which gradualy became rough idling and finally complete inability to start. The car had been inoperable at this point for around six months, so we guessed that the fuel filter was clogged and replaced it. The car started up with no problems whatsoever after that part was replaced.

Now a couple of days later the car is running rough again... what am I missing?

The roughness starts at 3300rpm in 1st, 3500rpm in 2nd and 3800rpm in 3rd, in 4th and 5th the car is smooth till 3000rpm or so. Is this an ECU problem or do I need to replace the entire wiring harness to begin enjoying the car again?

I should also add that the air intake butterfly valve is working smoothly and all electric ignition elements have been checked or replaced (distributor, wires, plugs etc)

P.S. Please don't tell me that I'm the only one with a 924s/ 944 with this problem... ever

If a new fuel filter solved the problem temporarily I would consider gunk in the tank, cloged fuel lines or booth.

I had considered the possibility but wouldn't the idle be rough and the car hard to start in general if clogged fuel lines and gunk were starving the engine of fuel? How could I check for fuel supply issues?

The engine might be hard to start or idle rough but it doesn't have to. On my 81 924 I test fuel supply by pulling the return line and measureing the output 750 cc's per 30 seconds.