5bucks
NAXJA Forum User
- Location
- Rochester, NY
In addition to my 99 4.0 XJ, I have a '98 grand 4.0. Starts beautifully but anywhere from 10-60 or so miles of highway driving engine looses power. If I try to give it any throttle it just gets worse. a couple times it has stalled. Most times it can stay barely running at idle, and sometime will go back to normal operation after coasting for 30 seconds or so. I can then go a few miles before it happens again. Other times best I can do is just coast at idle, get off the road, let it sit for a few minutes and then it starts like a champ only to go another mile or so till it happens again. The longer it sits after having a problem the further it will go next time. It has never happened when driving around town under 40mph for distances up to 15 miles. No CEL, but there is an old code for 02 sensor lean condition. Shop thinks it's a plugged catalytic converter that gets worse when heated up. I have the classic cracked exhaust manifold. They feel my converter is bad because the manifold is sucking air and causing the 02 sensor to tell the PCM to have the engine runner richer. I've driven this daily for 5+ years with the cracked manifold and no issues till now. Does this make sense? I thought people were driving forever with the cracked manifolds with no issues except some extra noise. The jeep is at a shop about 50 miles from home. I'm planning on going to get it this weekend. Drive as far as I can at lower speeds on back roads. Maybe I'll make it back. If not, next step is to pull the wires to the 02 sensor to force the engine to stay in open loop and continue the rest of the way. If that doesn't work I'll just sit it out till it cools down some and continue on a few miles and repeat. Any thoughts?