New Problems

[ghettoracer]

Apparently the truck being in the shop for 6 days didnt help. Had a misfire issue about a couple weeks ago, they found a leak in the EVAP canister solenoid, changed the spark plugs, changed 2 coils, changed the fuel filter. The things I noticed: when they changed the fuel filter, the entry end of the fuel line of the filter the gas came out brown, so after driving around on a hot day for an hour, the truck started to misfire again! This time the misfires were happening at 10 mph and 35-40 mph and much more noticeable. It got so bad that I went to the Ford dealership and parked it there. I figured that the misfires were so bad that I couldn't drive it any further and have Triple A pick up the truck and drop it off at the shop. I now have a new plan of action to see if this would stop the misfires:

Pull all the injectors, either get them cleaned or replace all 8 injectors. If that doesn't work pull all the coils and replace them with Accels or MSD coils. Apparently, the fuel injector cleaner didn't work.

Any suggestions or same problems?

 

[ghettoracer]

After extensive research, I believe I have found the culprit of these misfires. Looking at the F-150 forums, I believe that the coil boots are the culprits of the misfires. I do remember that the mechanic put in used coils for those misfires. Coil packs rarely fail, but the boots seem to be a major player in misfires in 5.4L Expeditions. Due to the heat, they create pinholes or cracks in the boots and make the spark jump creating the misfire. I am about 95% positive that they are failed boots. Going to switch out to stronger and thicker boots and more than likely going to put a fireproof boot sleeve on it so they dont get so hot. I hope this solves the misfire issue.

 

[ELVATO]

Hah, I figured by now you would have bought the ebay coils, and replaced all of them. Saved you all the hassle

 

[Stoned06]

The seals/boots are only there to keep moisture out of the well. If it was dry out, I would think that is not the cause of your misfires. If it is wet out, then that could likely be your problem. Aftermarket coils do not seal as well as the OEM ones. So if a good seal is what you are looking for, then go with OEM.

 

[ghettoracer]

Nah I think it was about time to change the boots because they would have aged through 150K+ miles. But it wouldnt be a bad idea to change the boots out and see what happens. I have a 1 in 3 chance that it could be that, but also it could be an injector issue or another coil pack issue. I have a good chance of it being the coil boots that are just worn out. The other guy on the F-150 forum had the same exact issue with his 5.4 and fixed it with new coil boots. Im guessing this is a common problem with the 5.4's like the spark plug blow outs.

 

[walnuts4x4]

less than 100 bucks you can get COPs on ebay and save a lot of future headaches... just my .02