Picked up an 03 TB LT EXT w/4.2. Was going to use it for parts but it might be better to put it back on the road if possible. Good interior and exterior. Starts instantly, but runs very rough, the engine shaking like crazy. Can move itself, but would not want to take it out on the road. Codes point to both the crankshaft and camshaft position sensors. Where should I start? Examine plugs & coils and do compression testing first? Or replace those sensors.
Troubleshooting rough running 4.2
- Thread starter Chilly
- Start date
christo829
Member
If it's shaking at idle, don't overlook the engine mounts. Does it smooth out any just by increasing the rpms?
Also, if you can view live data, watch for misfires. They won't always immediately throw a code, or may just show as a pending P0300. If they're showing any, that could indicate a coil/plug issue. Wouldn't hurt to check the condition of the plugs, either. How many miles on it? And if the plugs were replaced, check what they were replaced *with*.
Compression test wouldn't hurt.
Do you know if the crank and cam sensors have ever been replaced? If they were, and the previous owner used Dorman, those could be a bit suspect. Check the wiring for those sensors as well.
Good Luck!
Chris
Also, if you can view live data, watch for misfires. They won't always immediately throw a code, or may just show as a pending P0300. If they're showing any, that could indicate a coil/plug issue. Wouldn't hurt to check the condition of the plugs, either. How many miles on it? And if the plugs were replaced, check what they were replaced *with*.
Compression test wouldn't hurt.
Do you know if the crank and cam sensors have ever been replaced? If they were, and the previous owner used Dorman, those could be a bit suspect. Check the wiring for those sensors as well.
Good Luck!
Chris
Mooseman
Moderator
Like @christo829 said check for misfires. What are the exact codes you're getting? If the crank sensor was ever replaced, it may need a CASE relearn.
There's also the throttle body that may need cleaning.
There's also the throttle body that may need cleaning.
"When The Driver is Away...The Mice WILL Play..."
(1) A Bright Flash-Light
(2) M11 Nitrile Gloves (Protection from HANTA VIRUS carried by the NA Deer Mouse)
(3) N-95 Face Mask (Ditto)
(4) Eye Protection (Ditto)
(5) LARGE Zip-LOC Baggie to Collect Nesting Materials (Ditto)
(6) Wet Wipes (NO VACUUM OR AEROSOL CANNED AIR!) (Ditto)
(7) Under-Hood Inspection for Chewed Harnesses & Connectors
The GMT360 Images come courtesy @christo829
(1) A Bright Flash-Light
(2) M11 Nitrile Gloves (Protection from HANTA VIRUS carried by the NA Deer Mouse)
(3) N-95 Face Mask (Ditto)
(4) Eye Protection (Ditto)
(5) LARGE Zip-LOC Baggie to Collect Nesting Materials (Ditto)
(6) Wet Wipes (NO VACUUM OR AEROSOL CANNED AIR!) (Ditto)
(7) Under-Hood Inspection for Chewed Harnesses & Connectors
The GMT360 Images come courtesy @christo829
christo829
Member
And at the time the tree rats ate that wiring, I was driving the TB every day!