Quick question,
I've had cylinder misfires on 1,2 and 4 for a while now. I've tried everything to resolve this. After taking my code reader to AutoZone so they could read it, the 4 codes I got were for each cylinder, plus a "Multiple Cylinder Misfire" code. They told me I needed a Crankshaft Position Sensor. OK. Do I take their word for it? I thought I'd ask here to see what opinions I can get.
Thanks!
CJ

 

It could be other things, but the Crankshaft Position Sensor is a key component for multiple cylinder misfires. Especially when an aftermarket sensor has previously been installed. Here is a video that demonstrates the problem you mentioned, and was in fact solved by replacing the crankshaft position sensor.

 

If a new Mopar CPS doesn't solve your problem, another problem that folks with coil packs (00-01 XJ's) have is chaffed wiring for the coil pack. It would be worth the effort to check the wiring for both the coil pack and CPS while you're in there.

 

I'd start with when was the last time the spark plugs were replaced? Is there fuel or coolant in the cylinders when you pull a spark plug? If there's fuel you could have leaking injectors if there's coolant the head gasket might be blown. Then personally I'd probably go after the coil pack before the crankshaft position sensor since when mine failed it just wouldn't start or it would die randomly.

 

Detail exactly what you have tried.