GM 6.0L V8
6.0L misfire diagnosis
Ignition and fuel misfires on the 6.0L.
Why this matters on the GM 6.0L V8
High-mileage work engines wear out coils, plugs and wires.
Symptoms owners notice
- Rough running
- Loss of power
What we check
- Coil and plug tests
- Compression
Related causes we rule out
- Spark plug wires or boots damaged by heat from the nearby exhaust manifolds
- A failing coil pack or worn spark plugs
- Injector faults, especially on high-mileage work trucks and vans
- Vacuum leaks at intake gaskets, or low compression from valve or ring wear
Repair work involved
- Ignition repairs
Repair considerations
- On vans the engine is partly under the doghouse cover, which affects access and labor
- Swapping a coil or wire to another cylinder and watching whether the misfire follows it narrows the cause quickly
- A misfire with low compression points toward a mechanical repair or engine replacement rather than ignition parts