My 2004 GMC Savana V6 3500 VIN# 1GDJG1U141140461, misfire when it warms up. It stifles during acceleration. Small explosions can be heard in the exhaust system when the un-burnt gas ignites, while laboring to accelerate. What can be the problem? Vehicle has misfiring and O2 codes.
Repair the miss fires first and the o2 code may go away.
I would start with plugs, wires fuel and air filter.
December, 14, 2011 AT 2:02 AM
Vehicle has new plugs and wires, runs good when cold. It starts to shake when it reaches normal operating temperature. To prevent misfiring I would turn it off at stop lights and restart it when light turns green. If I allow it to idle too long, it will start to misfire and shake.
December, 14, 2011 AT 2:05 AM
Other possibles are injectors, vacuum leaks and coil failure.