My several previous posts on this issues are below. The car ran well for two weeks. This weekend, it quit on a long Interstate trip at 75 mph. It would only hold idle, would not take throttle, without sputtering and almost quitting. Replacing the fuel pump and radio supprtession relays with known good spares did not resolve. Let the sit 30 min. It started, eventually smoothed out, then ran fine the 90 miles home. Code at breakdown was 2-3-1 - fuel supply too weak or too rich in part load stage.

How can I diagnose a 2-3-1 intermittent fault? Any ideas? The car is driving me nuts. I want a diagnosis, not just replacing parts until it know longer fails - I'll never be able to trust the car otherwise. If there are no new ideas, I will be heading for a pro mechanic (utter defeat!).

Thanks!

Steve C

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Last nite, I cleaned the Idle AIr Cointrol Valve, no difference.
Installed new radio suppression relay, no difference.
Installed new aftermarket Ignition Module (Power Stage), ran very bad, faltering under power and stalling at idle.
Test drives produced no codes other than 1-1-1.
Pulled out the new IM and RS relay, and reinstalled the old parts, now it runs great?! 10 mile test drive and 12 miles suburban stop and go driving today have been flawless.

I cannot figure this one out. I think the problem is unresolved and will surface again.

Any thoughts?

Steve C

Previous posts:

"My original post from a few days ago is below. Since then I have verified the functionality of the Main fuel Pump, Tank fuel pump, mass air flow sensor, fuel pressure regulator, and throttle position sensor. Like I said in the earlier post, the fuel pressure relay was recently replaced a while before the problem started. I also attempted to find vacuum leaks using propane , but haven't come up with any yet. Inspection of the connectors for the ignition module and knock sensor were unremarkable. I retorqued the mounting bolts for the ignition module and its heat sink just to make sure.

I spent several hours Saturday reading up on the car then poking around trying to come up with a diagnosis. It seems that the car has several modes of symptoms. Sometimes, it will start and idle indefinetly, but will not take any throttle without stumbling. Somteimes the idle stays up at 1100 rpm, and the car stubles if you stab the gas pedal. Occasionally, it will barely run at all, or will not start. Occassionally, it will strat and drive normally for a few blocks, only to barely make it home running on idle because it won'ttake any throttle. The problems are independent of whether the engine is warm or cold.

I still am not sure what the diagnosis is. I am trying to figure it out before I just start throwing parts into it.

Any suggestions on how to proceed?

Steve C



"Greeting:

Today I had my 945T wagon quit a mile from home after a 5 minute warmup. Efforts to restar about 50 times produced no results. After about 15 min sitting, the car started, but alternatly sputtered, barely running, then would run fine for a bit. Engine felt as if it starving for fuel. Pulled codes, got two: one indicated that the fule pressure was either too low or too high, or that the engine was too rich; the other indicated that there was no signal from the knock sensor. The car has 126K miles, ignition tuneup and fuel filter within the last six months, and has the Bosch system, not Regina. This happened once about 8 months ago, but the problem cleared and has been running great since. How can I proceed to evaluate the problem?
Thanks.

Steve C"