2009 6.0L Suburban 1500 4WD. P0300, with misfires on #4. Previously had misfires on #5 and replaced the coil and that cleared it up. Replacing coil, plug, wire and injector on #4 has not helped. I feared valve lifter, but as this is a very intermittent problem that did not seem likely. I replaced the Valve Lifter Oil Manifold, and while in there scoped the camshaft
and it is pristine. Thoughts?
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: Intermittently for a couple of years - just the last year on #4 however. I am scanning it with a Snap-On Verus so I have fairly detailed code information. The ECU definitely thinks #4 is misfiring, and it runs terribly when it is happening.
JA: Are you fixing your Suburban 1500 yourself? What have you tried so far?
Customer: Yes and with the dealer also. See my first problem description for what has been tried so far. Also new intake manifold gaskets and camshaft position sensor.
JA: Anything else you want the mechanic to know before I connect you?
Customer: I think that is it - this is the first time I have tried this online chat - how does it work? I assume Pete does not sit online all day and answer questions for free?