Help!

[AR92]

i need some help with my 2001 wrangler with the 4cyl and manual trans. once it reaches operating temp it begins to jerk and occasionally back fires. I've been told its the pcm, crank sensor, and also was told the o2 sensor. I'm about to order a new pcm but i don't want to waste that much money and it not solve the problem

 

[JPNinPA]

With jerking you should be throwing a code. Read and post up the offending code.

 

[AR92]

its showing p1391 which is the crank or cam sensor but i have read that a lot of people have replaced both and it didn't fix the problem, which is why I've been told it could be the pcm

 

[Bounty__Hunter]

I'd start with the most common problem, the crank pos sensor.