View Full Version : P 0300 random misfire - 2000 STS

06-15-13, 05:46 PM
I have a random miss fire, i reaplaced plugs a coil packs two months ago. It doesnt seem to be a leak on the intake, egr its fine. Could it the problem be in the exhaust system?

06-15-13, 05:53 PM
Year make model? How many miles? Have you done a tune up?

06-15-13, 05:58 PM
2000 seville sts 135000 miles ,yes like two months ago

06-15-13, 06:08 PM
No intake leaks? Coils all good? Change the serp belt.

06-16-13, 08:50 PM
I got two stripped plugs in cylinders 6 and 8 , now what how can i fix that

06-18-13, 09:23 AM
This thread has nothing to do with "PCM Tuning". Moved to Northstar Performance.

Stripped plugs in 2 cylinders = new cylinder head OR a very, very lucky expert thread repair job by an awfully good shop. In a perverse way, you're "lucky" the bad plug threads are in the left (front) head.

ALWAYS place your car model and year in your profile. It sure makes diagnosis easier - due to radical differences in models/engines/years/parts.

06-18-13, 11:21 AM
Might look into Helicoil. They make thread repair kits for spark plug threads. Front side should be easy access.

06-30-13, 06:19 PM
Thanks, i took the car in to the shop. No striped plugs but the front ignition coil got replaced. They told me that the rear coil needs to be replaced. Well i ran the car for a week than abs and brake ligth and ttc came on .pulled the codes abs c1277 c1298 pcm p1571 p1644 and pcm u1040. I wonder if that rear ignition coil is making this codes pop up. When they come on the steering is hard and it feels like the car looses alot of power. Can some one help?

06-30-13, 08:46 PM
Without their definitions, codes are just numbers.