hey got an issue tryin 2 help a friend with. He has 05 f150 5.4 3v i changed plugs 4 him bout 2 weeks ago due 2 a misfire. Number 4 plug electrode was tore up like some plug 2 piston action had happen. Well all was well 4 bout couple weeks then he called me today with a mis agian it was on #4 cyl agian. So did the ol swap trick 2 rule out coil, spark plug ect. Well keep getting p0351. Sorry b4 i go any further i was a master tech 4 ford 4 10 yrs. so i know all the common things harness chaffing, broken wires, harness pins spreading, ECT. The only thing i wasnt able 2 do was check compression 2day. #4 plug was soaked wit fuel when i pulled it out so i put it in #1 and ran it for 5 min and it dried out. So the more time it took chasing the problem it started 2 smoke good white fuel smoke out of exhaust. My issue is im limited on diag info. like wiring diagrams n such so im tryin to save alot of time n money by getting input from you folks. Any suggestions will b greatly appreciated. Im thinking he has an injector issue but ive never in my time in the field ever seen a a coil primary circuit code 4 n injector but have come across a few post that suggest that it could possible happen. Thanks 4 the input.

 

Wouldn't it be easier to swap the injector and coil with another cylinder (one at a time) to see if the problem follows either of them?

 

Are you familiar with the defective injector issue on 2005s? There is an extended warranty on them. Sounds as if it my be stuck open.

 

https://www.f150online.com/forums/v8...ram-07m08.html

 

sounds like a stuck injector....#7 is a known one for going first.

I would swap out the injector and see if that fixes your problem...since you ran it for awhile there is a good chance you got the Cat in the process and possibly the 02 sensor on that bank of the engine.

 

I did swap the coil and plug it definatly not coil or plug and yeah i would do same wit injector except with the whipple charger on it its lil harder to just swap injector but thats the next step was short on time yesturday. I have read the customer letter on the injector issue truck is out of warranty 4 that its got 1700000 miles on it. B4 anybody post about charger its been on truck since bout 50000 miles pretty sure there r no issues there. Thanks 4 yalls input.

 

The only other thing that is kinda puzzling is the coil primary circuit code. Recon im gonna work on injector issue first then i worry bout CEL after that. let yall know how it pans out

 

By the way does anyone on here have pinout charts or wiring diagrams for the engine controls on this truck its 05 f150 5.4l 3v fx4.want to check circuits on the coils.

 

same symptoms changed plugs/boots o2 sensors, check engine light back on, pulled codes, several indications with timing, so changed the cam shaft position sensor truck idle smoothed out but idle was too high. Like a vacume problem. Mis was still there but not bad. So I reset the computer. Went back to puffin smoke and missing again. Havent messed with any coil packs yet.