David82

Always throws P0300, P0301, P0306 and nothing else. Jeep runs a little rough when first started, then smoothes out after a minute or two. Then, while driving, it runs fine, without misfiring for 20+ minutes, then will often start misfiring at stoplights and during deacceleration. The most important point is that the misfiring will go away if I restart the jeep. I think the problem occurs more often when it is raining/humid but not certain. It is always cylinder 1 and 6. I have replaced the coil packs and spark plugs. I've read every thread I can find on this topic. The threads where it is an intermittent issue on a 99+ model like mine don't have resolutions.

agreen

Try swapping injectors 1 and 2 first. Clear codes, see if it comes back or if it moves. THEN swap 5 and 6 and do the same.

Cylinders 1 and 6 are companion cylinders, so it's common for a problem with one to show up on both. Also, a p0300 will come up any time any other p030x is thrown.

David82

What leads you to think it is the injectors? What could be happening with the injectors to make the same injectors work, then not work, then work on restart?

agreen

The fact that it's a misfire on those 2 cylinders alone tells me it's likely something linked to just those cylinders. This is part of diagnostics. Move what you can around, see what it follows. It costs nothing but a little time to swap and see what it does.

Mike Rosas

i know this was years ago, but did you ever figure this issue out mine 01 is doing the same exact thing now.

Soleimpala

Did you ever figure yours out by chance??