I have a 00 f150 with the 5.4 108k miles and I have been having a problem with the truck misfiring. I replaced all the plugs and checked all the coil packs with an ohmmeter and everything seemed ok (I may have not used the ohmmeter correctly I don't have much experience). While driving you can tell the lack of power and when you get to over drive or try to accelerate quickly it starts jumping and sputtering horribly. It threw a misfire code and after I changed the plugs my light went off but the problem hasn't gotten any better. any help is greatly appreciated

 

The coils are not testable with an ohm meter. Do you know what the code was? Missfires are caused by a bad plug a bad coil, injector not working properly or lack of compression usually. Most common cause is the coil. That engine dose not have coil packs it has coil on plug or COP's. The generally begin to cascade fail (you fix one another goes bad) So its good to replace them all but they are pricy. Sometimes there are deals on Vistion coils but I dont know of any right now. If you had some one scan it who has a good scanner not the cheap ones but one that can see live missfire counts you could replace the one or 2 that has failed.

 

I had the same problem as you. I would change the plug and the code would go away for maybe 20 miles then come back up, never really fixing anything. The fix for mine was to just replace all the COPs. I bought some cheap COPs on ebay for I think it was $60 dollars, for all 8, and the problem went away.

I don't know how long the coils would last but they were recommended to me by another user here, so far they have worked great. If you've got the money its best to invest in some quality COPs.

As Jethat said you could find a someone with a good OBD scanner and have them set it up to show you the misfire count on each cylinder to see which one is misfiring and just replace that COP with a good brand. I couldn't find anyone who could do that so I just replaced them all with COPs i mentioned above.

BTW is it "jumping and sputtering" at certain speeds, say at 30 then at 45?

 

I just replaced timing chains, cam phasers, vct solenoids, and have it back together and it didnt want to start but I smell gas, but no fumes out the exhaust. when I put timing chain on I didnt take any roller followers out but held cams with vicegrip and lined up the colered links. what could it be.

 

Watch this video.