Hello all! This is my first thread on the forum, looking for some advice. Just moved from rochester ny to ocean pines md towing a trailer with my 04 f150 4.6. While navigating the hills of Pennsylvania, the truck would intermittently have a loss of power under load going up hills, then would return to normal after reaching the top. After awhile, it remained running rough and misfiring for the remainder of my trip. Had to keep going because I had a uhaul trailer and time constraints. When I reached my destination, I unplugged the injectors while running to listen for loss of Rpms. The truck seems to be only running on cylinders 5678. I also have oil in the intake. The kid at parts plus deleted all of my codes when trying to scan (great), but it was throwing misfire in cyl 1, lean bank 1, rich bank 2. I did the cylinder head last year for cylinders 1234 and replaced all spark plugs and coil packs. All cylinders seem to get spark. What would you guys start with? I was thinking vct solenoid but figured I would get some advice before I start throwing parts at it. Thanks! Matt

 

I would fix the miss fire on #1 first. I would guess coil, but there could be other problems. Fix the "miss" and you will reduce the problems significantly.

 

I would first do a compression test, followed by verifying that the gas was good, if the ignition is plug on coil, I would swap coils from known good cylinders and see if the misfire follows the coils, I know that on the 5.4 the coils are an issue, from time to time injectors can be an issue too. Not as many complaints on the 4.6 as on the 5.4, the 4.6 is known to be a very good engine.

 

Hey all I just replaced all pugs and 4 coil packs cylinders 3 4 5 6 had bad coil packs replaced all and pulled plugs out of 3 and 4 they had not been firing in a while as they were gummed up with carbon went to put new plugs in and can't get them to seat all the way u can here compression escape from 3 and 4 any Ideas on that and also now have code lean on bank 1 and 2 and misfire on 2 3 4

 

Hey all I just replaced all pugs and 4 coil packs cylinders 3 4 5 6 had bad coil packs replaced all and pulled plugs out of 3 and 4 they had not been firing in a while as they were gummed up with carbon went to put new plugs in and can't get them to seat all the way u can here compression escape from 3 and 4 any Ideas on that and also now have code lean on bank 1 and 2 and misfire on 2 3 4

 

I have a few questions, when you took the old plugs out, did you blow around them with a blow gun and compressed air? How did the old plugs come out, easy or hard? When you put the plugs back in, did you thread them in by hand or did you use air tools, my concerns are that you have at least two of them cross threaded or you have debris in the seat areas of the spark plug wells stopping you from actually seating the plugs, you will have to take those two plugs back out and see if there is damage to the seats and/ or the threads, hopefully not. The lean bank one and two codes come from the cylinder leaks on those two spark plugs, in essence, this is an intake and exhaust leak at the same time, hopefully you will be able to fix or repair this without pulling the heads, if you do have to use a thread chaser, heavy chassis grease will help keep metal shavings from falling into the cylinders.