2001 Expy 5.4. Had misfire on #4 replaced it, then put in all new plugs and bought cops off ebay and put in all new ones. Having misfire on 1,2,3. It did not set a code but still runs ragged. Had buddy at Ford check it good compression on all cylinders. It idles smooth but misses under load. He thinks it has jumped timing on passenger bank. Any suggestions I am pulling my hair out. Been able to drive it 2 weeks since I got it in Feb. Sorry for the rant don't know where to go next. Any help will be greatly appreciated thanks Jeep.

 

Just curious, but with no code set how did you determine that 1,2,3 are having misfires?

 

That is what the mechanic at ford told me. I do not know how he determined this. When I drove it home the MIL light was flashing so I hooked up my actron scanner at home and there were no codes or pending codes. This is what has me at wits end.

 

Did you save the COPs that came off? If so, replace the new 1, 2, and 3 COPs with the old ones and see if it smooths the engine out.