DiscGolfer74

I've read a ton of posts and a ton of Google searches and have yet to find anyone with anything that has helped. I know a lot of people don't like to read long posts so I'll try more of a highlights format.

• 2015 JKU Penstar V6
• 85,000 miles
• Random codes showing misfires in different cylinders with accompanying engine hesitation
• Been in the shop 3 times so far and replaced all plugs, coils, fuel injectors, and left cylinder head.
• I went to school with the owner of the shop and have no reason not to trust him. Says they've done leak down and compression tests.
• Every time I get the Jeep back, it runs fine for a couple of days and then the codes and hesitation come back and don't leave.

Obviously my first question is if anyone happens to know what's actually wrong with this and how to fix it. Secondly, would be if anyone can think of what would happen that when the shop pulls everything apart and puts it back together again that it'd work for a couple of days and then always fail after those couple of days. I feel like there has to be something key in that. Maybe some sort of particles in my fuel that take a little time to gather but then gets cleaned up when they pull everything out which starts the cycle again? Is that a thing? I'm an IT guy who can get around an engine okay, but many miles away from being a competent mechanic (hence why I've left this up to the "experts"). This has now been going on for months and I'm now ready to take the top and doors off and enjoy my Jeep again. Thanks in advance for any help.

casamtb

The timing may be as simple as the computer is resetting while unplugged being worked in. Then the computer is taking a few days to relearn. System codes that are vague have to be present a few times before they pop. What codes are you getting? And why was the left head replaced? Was there a leak/bad valve seat found? Was/is it burning oil?