2006 F150 5.4 flex 130k 4x4 Lariat

So I have a misfire in cylinder 6. Also very sluggish and slow in reverse, loss of power and throttle response.

I have recently had new timing chains, plugs, coils, wiring harness (all), runner control valve, phasers, chain guides, timing solenoids. All within the last 6 months trying to get it runner right.

I'm only getting a runner control valve code (even after changing it)

when we pulled the plugs the tips had chips missing off the metal around where it sparks. I am not a mechanic but I have 2 friends that both are and we have been doing all this in their shop. They are diesel mechanics so they said that their knowledge of the 5.4 is not what a normal mechanics is on the motor so i come here looking for some advice.

I just don't know what to try next or if If i should pulling timing chains and make sure they are right, just feel a little defeated and lost. Any guidance would be nice. I have been reading and searching so much that it has all began to run together and I just do not know where to go from here.

Before we started doing all this work on it a rat or squirrel had chewed the wiring harness but there was none of these issues but my friends said that while we were doing the harness we should go ahead put new timing and plugs and all the stuff we have done to it so I said sure since i had the help.

All of the parts were new besides the wiring harness (purchased Tested and working from local mechanic) and the runner control valve that came off another friends motor because his tranny broke and had been parting it out.

Thanks in advance for any help or comments of suggestions. Sorry for taking up yalls time.

 

Did you use Ford parts? Aftermarket phasers/timing chain kits usually don't work for long if at all. Is the engine making any clicking sounds? Rocker arm(cam follower) failure is a common problem but you would hear some clicking I think if that was the problem. The spark plug condition makes me wonder if they got the cam timing correct?

 

A diesel engine and a gas engine are essentially the same thing in principle. However, they work slightly different. However most competent diesel mechanics can also work on gas engines just fine. That is from my experience. Likewise if they got the timing off on a diesel engine, it would essentially not working right and there would be power loss or possible damage (head or even glow plugs).

It appears like Roadie said, a timing issue. Likewise if they got the timing off on a diesel engine, it would essentially not working right and there would be power loss or possible damage (to even glow plugs depending on where they are situated).

Where I'm getting at, and please don't take this the wrong way, you just need to take it to a competent mechanic or someone that knows a little bit more about engines than your friends do.

However, as a suggestion, I do recommend adding a Melling HV360 oil pump if you are putting this much work into the engine. The stock oil pump on the 3v is just not enough to keep everything lubricated.

 

Suggest knocking down the simple things before jumping to complicated, I would compression check the cylinder. Since you are all mechanics, I'll assume you have a compression check set. Get a new spark plug; I did get a bad plug once and chased a ghost for a few days. Swap the ignition coil to another cylinder, clear the codes, and see if the error code goes to the new cylinder. If it doesn't move, check the resistance/ impedance on the wire. Have you ever done an injector/fuel flush? Good luck.

 

A clogged cat on bank 2 will also throw a bank 2 frontal cylinder misfire, and also diminish power. Live data tells all. Simple scan to monitor the Baro, the O2 pre and post cat sensors, your fuel trims and your vct advance error PID. These will narrow down the issue.
if this issue threw DTC's, then check the freeze data and Mode 6. These 2 crucial modes of data collectors can paint a pretty clear picture of what is and has been happening with your engine.

Good luck and keep us posted.

 

I'm new here, but I had hesitation issues and it ended up being my plugs. Need to be replaced every 8k miles.

 

Correction....80000 miles.

 

He mention changing the plugs and still no change. Plugs and coils are usually the first go to suspects that get changed before even diagnosing the issue. The wiring harness issue would have me testing both the #6 injector and coil wiring for power and ground pulse. And if both those units pass operation status, then I would check the throttle plate on the throttle body. A dirty plate will render a vehicle useless if neglected. And if after cleaning that, you still have issues, take a 3lb sledge and hit the driver's cat with enough force to check for loose particles. If you hear loose stuff rattling in there, she's toast and needs replacing.

Good luck and Keep us posted.