So I have a 03 5.4 and it started idling rough again and its been misfiring but just changed plugs before winter any one can give me suggestions would help Sent from my SM-G960W using Tapatalk
@Scuba-40 Welcome to fordfullsize.com CEL light on ? Check Engine Light- Was di-electric grease put on the ends of the COPs to contacts of the spark plugs ? This is how I did the new wire ends to spark plug contacts on the 4.6L modular.
I haven't put any di grease on the plugs i thought about it. Engine light just came on yesterday haven't put my reader on it yet to see which cylinder has a misfire Sent from my SM-G960W using Tapatalk
Start there troubleshooting with the code reader. That will help you narrow down which cylinder to investigate. Maybe it has a code stored that is/isn't a misfire code. Been a while since you cleaned the MAF with specific MAF cleaner ? My fren always accused me of overkill on maintenance. No such thing ..
If you just did plugs, make sure all the connections are tight. if they didn't snap on, one might have wiggled loose. Next problem could be the COPs themselves. I had one that would only misfire in overdrive with slight load, took forever to figure out.
We'll work on this 5.4 having misfire next week when it returns from the installation of the brake pads and toyo tires, plus the alignment. It does misfire on overdrive.