2002 5.4L Bad Low RPM miss
Hello. I just want to say thanks in advance for any help, I'm eternally grateful. So, I have a 2002 F150 5.4L with 130,000 that is missing bad. It started slightly, only over 80-85MPH, then it got worse. I got it home, and then it flashed the check engine light at me. The codes are (5) of them: P0171 P0174 P0301 P0303 & P0316
Odd thing being I have O2 sensor cheaters in all 3 locations, due to the fact that my Catalytic converter is missing. :D not sure what those codes are about. Currently this setup has been running perfect for 5 yrs.
So, here's what I did. I checked out the 2 misfiring cylinders. 1 and 3 one looked like the injector plug came loose? Not sure how, but ok. Then cyl 3 had the worst plug I've ever seen in it. The ground was completely gone, looked burned. The plugs are all less than 5,000 miles old, autolite double platinum. The electrode was pretty bad too. Replacing the plug, and verifying spark, now installed, it's running worse. I now have a HUGE shake with the miss. and new codes. The miss is now all over the speed and RPM range, however, it's slightly better without load. They are, P0308 P0352 P0351
The cyl 8 misfire i think is a symptom, as the coil, and plug look great. I had a small vacuum leak at the PCV, i got a new valve and routed same diameter new hose for it. air tight now.
I'm kinda lost where to even begin. I've been 2 days on this and now I'm frustrated. I work for my church, so money is kind of an issue, which is why I'm doing the work, and posting here.
Thank you everyone,
Last edited by guy_over_here; 02-11-2009 at 17:45.