2003 Chevy Express 3500 6.0 P0300 intermittent code

Chevy Forum Chevy Classifieds Photo Gallery Chevrolet News Search Contact CF Sponsors
Member List Forum FAQ Chevy Timeslips Chevy Recalls TSBs Calendars Register Login

2003 Chevy Express 3500 6.0 P0300 intermittent code

Printable Version

Chevrolet Forum >> General Chevrolet Forums >> New Member Welcome Area >> 2003 Chevy Express 3500 6.0 P0300 intermittent code

Page: [1]

Message

<< Older Topic Newer Topic >>

2003 Chevy Express 3500 6.0 P0300 intermittent code - 10/28/2006 8:24:50 AM

warrennaujalis

Posts: 1
Joined: 10/28/2006
Status: offline

Hows it going
I was wondering if anyone has had any experience with an intermittent P0300 code (multiple cylinder misfire) on a Chevy Express 3500 6.0 or any vehicle with the 6.0 Vortec 6000. I tried changing the plugs and wires to no avail. The code will appear only on the highway when the vehicle is decelerating. A couple days later it will go away. But when I get on the highway again it usually comes back on. I had a mechanic friend of mine check the vehicle computer and the misfires he found were on the 1 and the 6 cylinder. Several thousand misfires on these cylinders were recorded. On his advice I took it to the dealer to check it out. There diagnostics indicated misfires on all cylinders especially the #7. The technician did not think it was ignition coils or ignition sysem he thought there may be a problem with a clogged catalytic converter. This dealer could not lift the vehicle due to the fact that it has dual rear wheels and a utility box on the back. I am taking the van to another dealer who can lift it and perform a cat back pressure test. However I am not having any driveability or power problems with the vehicle which would normally be associated with a cat problem. Anybody have any thoughts on this issue.
Thanks alot
Warren Naujalis