We had a reman motor put in. Started getting bad miss fire under any kind of load. I found one of the plug in's to the computer that the lock was not holding the connector in tight. It was not really loose, but was enough to cause bad contact. I pulled the plug out, contacts were clean. Put it back in and taped the lever down solid. Cured the problem and have not had any more issues. Thought this might help someone. This was a 2004 5.4. It gave misfire codes in several different cylinders.

 

thanks for the feed back....I'm sure that it will help someone somewhere

 

Yeah, thanks for the tip!