Moving misfire/hesitation and flashing CEL at W

IrocD · Post by **IrocD** » 12 Oct 2012, 19:54

Well maintained 01 S40 with just intake and MBC @12PSI in otherwise good health.

Recent fuel filter

My car will hesitate and misfire on different cylinders at hardish and full throttle with the dreaded flashing CEL. Sometimes it just flashes and has a pending code, then if not cleared after a few WOTs it will go steady and have a real code. I have tried swapping coils and wires, even using a brand new coil. I have replaced all the plugs too. Then I thought it was following the injector when I swapped those around, so I got another complete injector/rail/FPR setup from another boneyard. It seemed to help a little but its still there. Could it be the fuel pressure regulator? I don't have a gas odor or hard starts like I did when the FPR was bad when I first got the car. It would explain starving injectors right? Or could my pump be bad? So frustrating!

I'm aware of the damage misfires can cause, so I really hate having to force them to test possible solutions.

Otherwise the car runs great and at most throttle positions theres no issue. I don't get it! Any help would be greatly appreciated!

Post by **zulu-v40** » 13 Oct 2012, 07:56

What were the codes? Both coils could be faulty. Electrical wiring for the coils could be faulty. I've read lots of posts about people with flashing CEL lights that end up having transmission related problems.

IrocD · Post by **IrocD** » 13 Oct 2012, 18:21

The codes were misfires. My coils and wires seem so good, could it.really be both? I know it is most definitely not a tranny problem. I'm going to check the gap on the pre-gapped plugs.

IrocD · Post by **IrocD** » 14 Oct 2012, 15:14

Plug gap was the issue. The pre-gap was wrong and I made a rookie mistake by not checking. Runs beautiful now :)im

IrocD · Post by **IrocD** » 14 Oct 2012, 15:14

Plug gap was the issue. The pre-gap was wrong and I made a rookie mistake by not checking. Runs beautiful now :)im