bggordo13

I need help please I have tried everything car idles rough and has a slight backfiring sound while idling when driving seems to run fine after you get over 40 mph but stopped at lights or just sitting is horrible whole car shakes everything in the car is stock no aftermarket upgrades just changed all the spark plugs and wires had its scanned said it was a po300 then scanned again and it was a po306 so I checked the #6 cylinder and changed the coil and still runs horrible all the o2 sensors are reading fine changed all of them within the last year and the mass airflow sensor also nobody seems to know what would be causing this been in the shop over and over I am tired of chasing codes at this point if any one has had this problem or knows what it might be it would be awesome. Thanks for Your help!

WhiteHawk

Who are you taking it to? Was it a dealer? You might have an electrical gremlin in there and they have a machine that can piinpoint it at the dealer. If it was a dealer, i would ask for a refund if they charged you and couldn't figure it out.

I have seen a cracked spark plug cause that before. If it wasn't doing that before you changed them I would check them all.

-Geoff