I have an 2006 f-150 King Ranch with 103k miles and it was misfiring and then stalling when stoping at lights. Both cam shaft sensors and all coil packs were relaced then it was still misfiring. The head was recently replaced and now they are waiting on a new computer. When it starts misfiring it vibrates the whole truck and the engine light flashes. If you turn the truck off then back on it will run fine for about 50 miles. Im worried that replacing the computer is not going to fix it, what else could it be?

 

How long ago were the plugs changed and what kind were used?

 

It could also be coil boots. It sounds ignition related. What codes? I doubt it's the PCM. I have yet to have a PCM go bad on a Ford. I'm not saying that it never happens, just I've never ran across a bad PCM. I'd get the codes before I did any parts replacement.

 

The codes are continually throwing midfire 3 and 4 and camshaft sensor

 

I would service those codes first. I don't have an Emissions and Powertrain control manual here now, but if you can get one from your library or other source, it'll tell in the diagnostic routine which to service first.

 

Those codes have been serviced, thats why I was looking for more answers. The codes gets serviced then 50 to 60 miles same codes. I would start to question if the work was actually bring done if I didnt see it myself. I also want to add that this isn't costing me anything, I bought it used with a warranty. I just want it fixed so I can drive it and not this piece of scap metal that I have as a loaner.

 

OK so you still have misfires after changing plugs, boots, and what not.

Was this done at a ford dealership?

 

No it was done at the used dealership but they took it to the ford dealership yesturday and ase waiting on a new computer to be installed and programmed

 

OK have they rechecked the plugs since installing them?

 

I am not sure if you know or not but these engines only like motorcraft plugs usually and will have all sorts of problems with other plugs that is why I am asking.

 

They rechecked everything, they said the computer is throwing false codes but it sounds rather stupid to me, maybe its because I'm a chic and they think I'm automotive stupid or something

 

I know a mechanic or two like that they always think women can't possible know anything about their vehicle. I would ask them if they used motorcraft plugs and then repull the ones on the cylinders giving trouble. I know they have checked lots but I talked to a guy on here who had a trusted mechanic so they went threw everything like you are doing and then they changed the plugs again and put in motorcraft and the problem was gone.

 

I read of someone else who had a similar issue and found out the mechanic had broken one of the plugs (which is pretty standard) on these engines. But he didn't want to spend the time getting it out so he left it and changed the rest and hoped no one would notice.

 

Champion plugs do as well as Motorcraft. I have found that if it's a spark plug issue on these trucks it's usually due to the person changing plugs, not the plug itself. But it's possible as Drew said that they didn't change out a broken plug or two on the cylinders you are having misfires on. It's also possible that they got some anti-sieze on the electrodes of those two plugs. Another thing I would check is whether there is any chafing or bare wires in the COP harness.

 

Greg I have seen too many post on this forum and another to agree with you about the Champions in these motors. Most people are replacing the champions within 10k after the original replacement.