I have a bad misfire on my 91 4.0 liter. Clears up around 2000 rpms. Did a compression check and I think its the rings. Misfire has been going on for quite the while so i think my heads are probably shot from the bad rings, not to mention light damage to the block, and probably shot connecting rods. Do you think it would be cheaper to fix, or just a complete engine swap? O yea I have 153,xxx on the motor. Comments and Suggestions Appreciated!

 

a used engine swap is going to be cheaper than a rebuild...... if you could rebuild it yourself and not have major machine work (no boring,no crank work) just cyl head rework, vatted, freeze plugs etc you would be lucky to get out for under $1100. buying one already rebuilt is $1500 up + install.

Ive had good luck buying whole wrecked parts cars using what i need and then sell the rest. If you can pick up a 2wd 91-96 thats been smashed in rear or something (where you can still hear motor run)for $500-700 you get a good motor and sell all the rest for $300 you are way ahead.

 

your problem could be a bad injector especially if it clears up at higher rpm becuase ur gaining more fuel pressure if your truck is blowing alot of smoke from your dip stick or fill cap, or tail pipe u can put ur money on rings but if thats not to bad it could be a spark plug or injector

 

thanks for all your help, im probably just going to go with the engine swap because i ripped my heads off and they are completely destroyed, and thanks lolz jeep but i checked my plugs and distributor cap so i know its not an electrical problem, im probably just going to go with the all out engine swap

 

mine did this... the code went away after I fixed a blown fuse on the radio of all things...

 

haha thanks for all your help, i just swapped motors a week ago and the problem is solved, turns out it was the first piston because the rings collapsed and i had to pour oil in the first piston to get the compression up just to get it started. only 400 bucks for a junkyard motor and it runs better than before so it was worth it.