poolman said:
wife's Suburban, 5.3, little over 100k burns a little oil not much but it goes through these spells where it runs like crap, has a miss, may not want to start all kinds of stuff.
poolman said:
07 suburban, it will run fine sometimes, then at random it will start missing, and the wife says once a week it doesn't want to start. Sometimes at idle it will be running fine then it will miss, I can see a very little bit of black smoke, ( fuel I'm assuming) and then it goes back to normal.
poolman said:
I think the code was multiple misfires? That's from the last guy I actually trust to look at it, he also replaced a o2 sensor. Everyone else has said, rings, heads, ect but after a compression check everything was over 110 I believe
Quoted so I can read all the story in one place. And finally got to a laptop so I can type a decent response.
Check the fuel injector wiring, corrosion on pins at ECM on the blue connector, look at where the harness goes around the battery box and see if it's chaffed and grounding injector wires. Have the motor mounts started tearing up and going thump when you get on the gas? Could be pulling on the harness.
Spark plugs been replaced yet, what did they look like when they were pulled for the compression test?
Fuel pressure good when driving or under load? Pump may be leaking down after sitting all night, or for long period of time. Does it crank right back up if it has only been turned off for a few minutes, like going into the store for a case of beer?
When it throws a misfire code, look at the data stored and see what degrees the coolant temp sensor is at, if it drops to -34 or something stupid then it has a "dead spot" in it and is causing it to go rich.
If it was mechanical, I think it would misfire all the time, not randomly.
Hope that helps, if not tell me to
