Wonder if anyone has had this and what they did? Truck was running well. Stopped at a light. When I started up again it started misfiring so bad it barely would idle. Limped home and got all the above codes.

I swapped the coil from #2 to #1. Cleared the codes. Same P0302 & P0351 came back.

Would have expected the P0351 "Bad Coil A" or P0302 "Cyl #2 Misfire" error to have moved but didn't.

But I'm also wondering does "Bad Coil A" refer to Cyl #1? I think "Bank A" usually means #1 cylinder.

From what I am reading it could be a broken wire too. Does anyone know where to find a ECM pinout to test continuity to the coil?

Thanks

2004 F150 Lariat 5.4L 4X4
110k Miles Totally Stock

 

P0351 indicates an electrical problem with the circuit to the ignition coil. The code's description is something like "Coil A primary circuit fault," but just use the code's last number to determine what cylinder it's referring to.

If someone else doesn't find them first, bare with me and I'll try to dig some wiring diagrams and stuff up for you. I'd work on fixing the P0351 first, then go from there.

 

Quintin,

Thanks for the response. Does the "A" in "Coil A primary/secondary circuit" refer to cylinder #1?

 

Yes. A is one, B is two, and so on and so forth.

What's your E-mail address? I think I got some .pdfs and some captures out of the wiring diagram to send to you.

 

Quintin,

That's what I thought. That makes the codes that I'm getting a little odd. They say the coil circuit is bad in #1 and I have a Misfire and Lean Condition in #2 simultaneously.

That would explain why swapping the coils between the two might have no effect. They both may be misfiring.

I'll swap a coil from #1 over to the other bank and see if I get a new code in that side.

The problem feel like more than one cylinder is having a problem. The is starting to feel more like a ECM issue.

 

Any news?

I wouldn't rule out the PCM, it's just that I've seen more wiring problems (pinched/broken wire in the harness, loose pin fit, etc.) causing problems like you're having than faulty PCMs.

 

I gave up and took it to the dealer. They pulled the valve cover and found metal everywhere. They presume a spring broke, the follower came off, the rocker exploded, bent the valve, etc.

There isn't any noise that sounds like metal in the cylinder, but I'm sure whacking the valve didn't do the piston or the valve any good. I'll have to pull the head to see if all it needs is a new head. Is it correct that the engine needs to come out to swap heads?

So the dealer recommends a new engine at $5895. I am going to have it towed home and work on it as soon as it warms up.

I have the 2004 5.4 DOHC. I found someone with a new in the box head for a 2002 5.4 DOHC. The part numbers are not the same. Does anyone know what the differences between them might be? What years will interchange with the 2004?

Thanks,

Depressed...

 

No, you don't have to pull the engine to get the heads off. It's easier, but it's not impossible in chassis.

Your '04 is a SOHC engine, with 3 valves/cylinder. If you're going to swap the heads, any other 3V head will bolt right up. If you're gonna re-do the heads you have on the truck, you'll have to use 2004 model year parts since some valvetrain stuff changed in '05+ engines.

I've seen a few broken valve springs on 3Vs, one where it dropped a valve and totally scattered the engine from top to bottom. Big chunks of aluminum in the oil pan, it wasn't pretty. That still doesn't explain your P0351, but I don't suppose it matters at this point in time.

 

Hi! How did you fix your problem? I have the P0351 code.

 

I have a P0351 code since yesterday (again) would you tell me how did you fix I don`t remember how i fixed mine five months ago! Thanks!

 

Art, how many threads are you going to bring back up?

 

Hi! 2 are ok! By the way problem fixed switching COLIS 1 and 4.

 

I'm having the same issue with my 2004 5.4 triton, can you please email me the wiring diagram.