No spark sometimes. 92 XJ

All

I have a 92 XJ that fails to start from time to time. It cranks well but dosn't catch. It will do this 2 or 3 times and then it starts. When it won't start there is no spark from the coil. Once it does start, it runs well. It's hard to diagnose because it happens very seldom. The only other problem it has is sometimes it bucks when it is accelerating.

So here's the question. If I can catch it failing, and see that there is no input to the coil, what are the possible causes?

Crank sensor
Cam position sensor
Bad coil

Anything else?


Thanks
Marc

You have identified the usual suspects.

For the 91-99, the top suspect is the crank sensor; ignition coil is a possibility. Usually, when the cam sensor fails, you will have spark....but there does seem to be one way that it fails that inhibits spark.

If you buy a crank sensor, buy it directly from Jeep. No lack of threads of people having trouble with some (not all) aftermarket crank sensors. And considering that the crank sensor is the most critical sensor on the 4.0, paying a little extra money for the one from the dealer is money very well spent.