Code PO300 [Archive] - Forum


View Full Version : Code PO300

05-02-2004, 09:23 AM
My Girlfriend has a Grand Am SE. It is missing badly. Autozone said the code is PO300. Does anyone know what this could be?

Mike Jung
05-02-2004, 11:19 AM
P0300 = Random/Multiple Cylinder Misfire Detected

Mis-fire = BAD!

Maybe needs:
new spark plugs & wires,
ignition coils,
fuel injector flush/cleaning via fuel system rail (it might be clogged) &/or fuel filter change (it might be clogged & need changing).

Flashing SERVICE ENGINE SOON light means severe mis-firing currently happening.

05-02-2004, 01:04 PM
Flashing SES light also means DONT run car! Possible engine or converter damange could result

05-02-2004, 09:14 PM
during a misfire would it shake the whole car really badly?
last night the whole car shook badly then when i shifted into gear it damn near died or if i turned the wheel it would too, so i put it back into park and shut it off and restarted it and it was unchanged.
SES was solid then flashed for a while then was solid again then flashed some more.

05-20-2004, 06:47 AM
Hey, I've got misfire code P0304 - Misfire Cylinder 4. Not a blinking code but it came on about 1 1/2 mins after leaving the house. I'm wondering if I should try changing the plug first or if I should just see if the code comes back(had it checked and cleared by Autozone). The exhaust makes an occasional soft "spitting" sort of sound about every 3 seconds, I think its the engine missing, is every 3 seconds too many misses or should I ignore that because my friends GA and my moms GA do it the same way as mine?

05-20-2004, 07:50 AM
^ See if perhaps the plug wire is loose first. Then you can try the plugs and wires. I wouldn't ignore it for too long. A misfire is a misfire, and it's never good for your engine.

05-21-2004, 04:56 PM
Hmm, I think it was just a few misses as an isolated incident, if the light comes back on ill change the plugs and wires, i've only got 37k miles though. I regularily run a can of sea foam through the tank every 2000-3000 miles, and its been about 750 since the last time I should do it so i wouldnt think injectors, so maybe a plug got a little ugly. I'm not going to worry about it unless I see a light on again. :slayer