OK...I'm driving hime and the car starts to surge a little,the RPMs fluctuated aand as I got in my road...it dies.I coasted to the side til I stopped and restarted the car.I made it home and as the car was idleing,it cut off.I turned the key to the run position and heard the fuel pump..ok.Cranked the car and it ran but RPMs would go up and down then smooth out then the engine would die again.There are no Service Codes in the ECM.I believe in order for a code to set, the problem has to exist for at least 15 seconds.But,I'm thinking this is intermittent and the problem shuts down the engine and never sets a code.The timing is good at factory spec.The car has been tuned up last month and I cleaned the IAC valve.I tested the ECM to se if it would hold a code by disconnecting the TPS and let it set a code 22.After jumping the ALDL, the code 22 was there telling me the ECM can store codes.I read where the battery cable might be a problem.I was wondering if you guys can help me figure this out before I start throwing parts in it first.

Ken
91 RS V6 Auto

 

Im having a similiar problem at the moment

 

12 is what you rlooking for, 22's not the check code

 

Code 22 is the Throttle Position Sensor.

 

Right....the ECM threw out the normal code 12 at first.The ECM did'nt show any other codesstored.So,I unhooked the TPS intentionally to set a code 22 to see if the ECM would hold it thus eliminating the chances of it might being a bad ECM.'

Ken

 

Sounds like a vacuum leak, or the egr could be stuck open. Neither of these will set a code. My '87 would surge when it was cold but was fine once warmed up. That was a bad temp sensor. But, this started while you were driving? So already hot.

 

Check the EGR first. SOunds like it could be the culprit.

 

Is there ANY way I can check the EGR valve?I know its digital but I'm wondering if I can unplug it to see if there is a difference even though it will set a code in the ECM.Has anyone ever driven with one unplugged?

Ken

 

Well...i unplugged the EGR valve connector and no go.It seem to idle kinda high, but it ran smooth and then died out in 10 seconds.The engine was cold so I'm thinking its not temp related.My second guess is the IAC valve.It might cause the car to die out if the pintle is'nt right.Any thoughts on this new development?I noticed the engine would kinda "bump" after it died kinda like fuel maybe getting burned off.

Ken

 

Im having a simular problem Id like to know if you have any solutions yet. Brian

 

Well...my problem was due to 3 things.I had the ignition module give out on me.The fuel pump relay needed replacing.I went and replaced the oil pressure switch just in case.I would try the module first.Then,just unplug the fuel pump relay connector while the car is running.If it continues to run,it is'nt the relay.Cut off car,re-connect fuel pump relay connector then cut car back on.This time, unplug the oil pressure switch.I narrowed it down to a bad relay in my case.Let me know.

Ken