2002 Cadillac STS

Engine Performance problem
2002 Cadillac STS V8 Front Wheel Drive Automatic 160000 miles

P0306 Misfire Code
Have tried. Coil, Plugs, Injector, Intake Gasket, Ignition Control Module. All Cylinders have 175 lbs Compression. Any ideas?
March 28, 2010.

Sounds like youve tried most possibilities. You could have a broken valve spring, or a follower that came off. You will still have compression, It will possibly build faster. The only other possibility would be to check that the #6 injector is firing, you would need an injector test(or noid) light for that. What condition is the spark plug when you remove it from #6 cylinder, is it wet?

Mar 28, 2010.