Ok, as much as it pains me to say it, I am about to write Jeeps off....I am on my third Cherokee and am having issues with this one now too. Maybe its just me, but I do regular maintenance and don't abuse them.

I just finished swapping my lift, skid, plates, bumpers, and various other parts from my last XJ to this one. It has 120K miles and ran fine the last few months.

Anyway, I am driving down the road and my MIL light starts flashing yellow at me. I stop at a light and it starts running really rough. As I start to accelerate there is a large loss of power and the whole thing is shaking. At speed when I let off the gas everything smooths out, then the vibes start as soon as i touch the gas. I pulled into AutoZone for a scan and it shows cylinder 5 misfire.

I swapped out the coil pack and the #5 plug hoping for an easy fix....no luck.

Any thoughts?

 

#5 plug wire?


Any drops in gas mileage?

 

Should have put in the specifics eh? Its a 2000, no wires. Swapped the whole coil pack, and it just happened yesterday and I have not driven it today so no clue on the mileage thus far.

 

1. Swap the fuel injector from cylinder #5 to a different cylinder and see if the misfire follows to that cylinder.

2. Run a compression test on all cylinders and see where #5 sits in comparison to the others. First dry, then wet test if any cylinders read low initially. Can't rule out an internal engine problem as you work through this. The compression spec for the 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders.