- Aug 19, 2014
- 83
Hi all,
For the past 2 years, I've been chasing an issue that I cant figure out.
I am getting a misfire after the engine is fully hot. Usually after driving for 30 mins or more.
This causes fuel to get dumped into the Cat, and I've had two Cat's replaced in 3 years.
It misfires the worst with cruise control on and going up a slight uphill. REALLY bad stumbles there. Most of the time it does not throw a code, but when it does it rarely identifies which cylinder misfired. Usually its the "random" misfire code.
I have done all the regular stuff. Cleaned the throttle body numerous times.
Changed the plugs (iridiums) at least 3x, changed the ignition coils 3x. Changed the VVT.
One thing I have noticed is the plug tips are burnt almost completely off on some cylinders.
I dont know if this happens because of the misfire or if something is causing them to burn up quickly.
After I change the plugs and coils, the misfire will go away for a few months and even longer. Then it comes back.
Any ideas ?? Its a 2004 Bravada with 200k miles
Mark
For the past 2 years, I've been chasing an issue that I cant figure out.
I am getting a misfire after the engine is fully hot. Usually after driving for 30 mins or more.
This causes fuel to get dumped into the Cat, and I've had two Cat's replaced in 3 years.
It misfires the worst with cruise control on and going up a slight uphill. REALLY bad stumbles there. Most of the time it does not throw a code, but when it does it rarely identifies which cylinder misfired. Usually its the "random" misfire code.
I have done all the regular stuff. Cleaned the throttle body numerous times.
Changed the plugs (iridiums) at least 3x, changed the ignition coils 3x. Changed the VVT.
One thing I have noticed is the plug tips are burnt almost completely off on some cylinders.
I dont know if this happens because of the misfire or if something is causing them to burn up quickly.
After I change the plugs and coils, the misfire will go away for a few months and even longer. Then it comes back.
Any ideas ?? Its a 2004 Bravada with 200k miles
Mark