My 03 f150 5.4 is idling at 1200 rpms. I've been having jerking issues between 50 and 60 mph, but has gotten worse. Like i said it is now idling at around 1200, but fluctuating. I unplugged the coils one at a time during idle and the idle dropped on all but one. Could this be just a spark plug?

 

With a rpm of 1200, I would be looking for a vacuum leak

 

Sounds like it's hurtin, - more than just one problem. Like torkum posts along with a coil or plug. You could have IAC problem, MAF as well. Time to maintenance, - go thru a few things. What plugs are you running?

 

Or injectors...don't forget the injectors..

 

I've replaced the EGR and DPFE with no results. The engine light never came on to give a code until tonight, it began flashing and went off again. I suppose i should start by replacing the plugs. I can't find a vacuum leak. By the way what's the best way to find a leak?

 

I'll try again lol - What plugs are you running ???