I have a 2001 Cherokee. For the last several years everytime I put it under a load ie: pulling a boat, putting on the AC it starts to idle rough and the CEL comes on. It also does it when I have been driving for a while and stop for gas and then restart. The code is misfire in cyl. #4. Whenever it happens i mearly stop, remove the negative terminal for 10 seconds & replace. It then runs fine until the next time. My mechanic thought it was a leaky head gasket but i am not losing any water or oil. Also if it was the head gasket why would it run perfect after i reset the computer. I have been reading about "heat soak", could this be the problem? I have had the chargers replaced twice but no change.

 

i have read about the heat soak and it affects injector #4 so i would look into what the fix is for it and go at it and it would make sense you would usually see it under load