Contour Enthusiasts Group Archives Forums General Troubleshooting Calling all Cops...I need help...

No, I'm not in legal trouble but, I'm gonna be when I run this car off a cliff!
I still have a single puttputtputt misfire or "incomplete combustion" (it fluctuates)that only seems to affect idle. The car runs absolutely great under hard acceleration even down to 1/8 tank of gas. I got this problem one day while trying to fix my stumbling/stuttering (given up for normal)problem. Meaning one minute it wasn't there and the next it was. So, I assume it has something to do with ignition. When it first occured, I was checking (ohming out) the coil and wires. On restart it had a slight misfire. This "misfire" comes and goes...it's worse when hot and seems to have a mind of it's own. Mostly there but like I said, goes away almost completely sometimes.

No codes generated in Vehicle explorer.

Is there any way the PCM can trim a single injector pulse width?

I have since replaced with no effect...

UIM / LIM gaskets. (zero change)
spark plugs (AWSF32F) (APP764 too, no difference)
Magnecor wires (zero change)
coil (switched back and forth, new / old)
DPFE (in search of the stumbling)
injectors (zero change)
Cleaned TPS (volts are good at idle & WOT)

I have cleaned with electrical cleaner all related connectors from the injectors to the fuel tank. Still no change.

This seems to be a secondary ignition problem, but so far has eluded all logic.

...Ed

Have you thought about replacing your fuel pump? Seen a few posts recently complaining about common failures on the returnless "smart pump"?

Timing?---may be off enuf to affect it.

don't know if it's equiped but sounds like the fuel pressure regulator.

???
my .02

later
MP

Fuel pump? Hmmm. All my fuel pump failures were marked with a absolute inability to accelerate past 6k on 1/4 tank or less. I do not experience this now. The car seems to run great off idle. Still stumble/burbles along though...I have given up on this problem and consider it "normal" EPA lean programing.
As for the fuel pressure regulator...it was replaced along with the fuel rail.
I have checked for bad vacuum lines and tested (passed) the EGR valve and almost anything you can associate with this problem.
My only thought is again with the coil...as I have always said (repeated)"The first thing to go wrong is the last thing you fixed". Can you harm a coil by ohming it out incorrectly? I'm sure I touched the wrong DigitalMultiMeter lead to the wrong lead once or so. Could that fry a coil...I sure wouldn't think so.

I'm going to go get a can of starting fluid and spray it around and see if I can get a rise out of it.

...Ed

If it's only at idle, it could be your Idle Air Control module/motor ("IAC"). Common problem, easy fix(es).