misfire, no code set [Archive] - GrandAmGT.com Forum

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DucksInARow
03-05-2008, 11:45 PM
Hi All,
I'm currently in the process of pulling my hair out.
I have a 2001 GA SE, 4 cyl. I've had an occassional misfire for a while. After changing both coils, the coil housing, all 4 spark plugs (used delco platinum), ignition module, plug boots - the thing is still missing!!

Since I've changed all that stuff it has gotten better. Previously I had P0303 - mis on cyl 3. Changing the coils fixed that. But now it's missing occassionally and it is setting no codes.

Usually when I'm accellerating at the bottom of 2nd or 3rd gear the misfire is most noticable. But it won't do it every time I'm in 2nd or 3rd gear. Some days it's more common than others, but there are no codes being set. RRGG!!

When the missing was really bad it burned through a cat converter. I think the cat I've got now is breaking up because I can pound on the can and hear some rattling. Can a clogged/breaking up cat converter cause a misfire??

I've searched the forum for misfires but most things I've already tried.

Any further suggestions??

Mike Jung
03-06-2008, 04:46 AM
Clogged fuel filter ?

Clogged fuel injector ?

DucksInARow
03-06-2008, 01:03 PM
Yeah I also changed one injector (also on cyl 3). I took the car to a shop and they said they ran a fuel system pressure check using the scan tool. It said all the injectors were reporting full pressure and no leaks. But I guess that wouldn't tell me if an injector was clogged. Is there any way to check for a clogged injector??

I also changed the fuel filter. Forgot to mention that.

DucksInARow
03-09-2008, 12:38 AM
How about a bad ignition module? Again, I have no codes stored, but could a failing ignition module cause a misfire?

I'm running out of ideas. I can check the injectors with a fuel pressure test again, but if there was a tiny grain of sand, say, stuck in an injector would it necessarily cause a leak?