Hello I have a 2000 f150 5.4, and have done lots of work to it. But for a while now I have had a cylinder 4 missfire and recently now cylinder 1 joined it. I have a spare engine from when i swapped mine out and have gone back and fourth with ijectors and coil packs but still no change,brand new spark plugs, swapped out the egr and evap sensor. and still no luck,I did a compression test on the cylinders an got a 167psi wich isnt bad. the truck seems fine till it gets at highway speeds or even a big hill, then just shakes beyond belief generally while in overdrive. I am awar of the heater hose leak and it is not that, just wondering if anybody could have a possible idea to what is wrong, thank you- Nick

 

What brand of plugs was installed? May need to change all the cops out with new ones.

 

Umm I believe they were champions. Wierd thing is i pulled them out of the cylinder and they had spark?

 

these engines do not run well on Champions, you should replace them with Motorcraft plugs

 

motorcraft only.

 

Definitely change the plugs to motorcraft. Torque to 28 ft. lbs., no anti-seize.