Originally Posted by smj999smj
It would be helpful to be able to look at the datastream info with a scan tool, but, unfortunately most don't have that option. Checking the fuel pressure is a good idea to rule that out as a possibility. Pressure spec is 50 psi. You'll need a fuel pressure gauge that can connect to the quick disconnect fittings where the fuel line connects to the front of the left bank fuel rail, at the front of the engine. You will also need the correct tool to disconnect the fuel line from the rail. Cam position sensor and crank position sensor failures are fairly common on these engines and don't always trigger codes. They can also cause driveability issues that can trigger other codes. Another area than can cause some driveability issues is the battery cable connections. Sometimes it's difficult to get the clamps tight, which results in poor connections, so make sure you can't turn them by hand on the battery posts. By your description, it doesn't sound like a clogged catalytic converter issue.
Thanks. I did shy away from checking the fuel system since it's been hard to get to a parts store the last few days. I may try that tomorrow while I can get a ride, but need to try to research it more tonight.
Here is what I've done since the last post:
- Truck is towed home and easier to work on
- Did a compression check and all 6 cylinders are making good compression (this should rule out timing too right?)
- Verified TPS sensor should be working (butterfly valve opened when holding pedal down)
- Pulled the coil packs and tested them with a multi-meter, those checked out fine.
- Pulled both cam position sensors and both tested fine. The passenger side one looks like crap but still tests fine.
- Removed the passenger front o2 sensor and started it, since this is before the cat it should let it breath if I have a clogged cat, but I didn't do this on the drivers side. I'm not sure this is worth bothering with on the drivers side since creating an airway on the passenger side didn't seem to help.
- I pulled the MAF sensor plug off while the truck was running and the idle changed, but it didn't cut off. I was also able to start it without the MAF plugged in. From what I read this should prove the MAF is OK. We tried testing the plug but there isn't room to get anything (even a piece of thin wire) in to probe and didn't want to cut the wires.
- Checked out battery cables and it's got a solid connection on both sides, battery is less than 6 months old BTW.
What else to check or I suspect:
- Fuel system (could be injector or fuel pump, will use quoted advice and test the fuel system soon, hopefully tomorrow)
- Intake air leak (I sprayed some brake cleaner around the intake manifold a few days ago and didn't hear any idle change, but I'll try this again).