Hey, guys.
Just bought a 140k miles '98/99 WJ w/ 4.0L (see https://www.naxja.org/forum/showthread.php?t=1165164) sight unseen. Not many miles into the 500 mile trip home (half of which pulling a 4k lbs trailer) CEL comes on and a sporadic sputtering presents itself. The sputtering appear as sudden bursts of power loss, primarily when cruising/coasting (and apparently never under load), but predominantly when idling (as a frequent 'poofing' from the tailpipe).
Other than the occasional sputtering, the car did not feel sluggish or low on power (I am calibrating that based on my experience with 800 lbs lighter 4-litre XJs with less power-absorptive transmissions), and I seemed to get normal gas mileage (22 MPG cruising/highway and 15 MPG with trailer). Oil and coolant both looks fine.
Only code it is throwing is P0302 (Cylinder #2 Misfire Detected). Not knowing whether I have the 0331 cylinder head (the oil filling cap is just spinning), I started the diagnostic process by checking plugs (they seemed to have som oilish sludge - see picture), and proceeding with cylinder compression, with the following readings (cold motor):
Cyl. #1: 149psi
Cyl. #2: 160psi
Cyl. #3: 156psi
Cyl. #4: 148psi
Cyl. #5: 162psi
Cyl. #6: 65psi (!)
Of course, I was pleased as punch until reaching the last cylinder. Thinking I maybe didn't get the rubber boot of the compression tester on properly (it's tight/crowded), I tried to verify multiple times.
So, what are we dealing with here? Head gasket? From what I understand, the infamous crack (almost always?) happens around cylinder 3 and 4? And why would it indicate cylinder 2 through the OBD?
Thanks in advance!
Just bought a 140k miles '98/99 WJ w/ 4.0L (see https://www.naxja.org/forum/showthread.php?t=1165164) sight unseen. Not many miles into the 500 mile trip home (half of which pulling a 4k lbs trailer) CEL comes on and a sporadic sputtering presents itself. The sputtering appear as sudden bursts of power loss, primarily when cruising/coasting (and apparently never under load), but predominantly when idling (as a frequent 'poofing' from the tailpipe).
Other than the occasional sputtering, the car did not feel sluggish or low on power (I am calibrating that based on my experience with 800 lbs lighter 4-litre XJs with less power-absorptive transmissions), and I seemed to get normal gas mileage (22 MPG cruising/highway and 15 MPG with trailer). Oil and coolant both looks fine.
Only code it is throwing is P0302 (Cylinder #2 Misfire Detected). Not knowing whether I have the 0331 cylinder head (the oil filling cap is just spinning), I started the diagnostic process by checking plugs (they seemed to have som oilish sludge - see picture), and proceeding with cylinder compression, with the following readings (cold motor):
Cyl. #1: 149psi
Cyl. #2: 160psi
Cyl. #3: 156psi
Cyl. #4: 148psi
Cyl. #5: 162psi
Cyl. #6: 65psi (!)
Of course, I was pleased as punch until reaching the last cylinder. Thinking I maybe didn't get the rubber boot of the compression tester on properly (it's tight/crowded), I tried to verify multiple times.
So, what are we dealing with here? Head gasket? From what I understand, the infamous crack (almost always?) happens around cylinder 3 and 4? And why would it indicate cylinder 2 through the OBD?
Thanks in advance!