Ok guys here is the deal about a month ago my truck started acting like it was skipping. Had local mechanic Change out plugs coils injectors and fuel filter. Picked up truck ran fine as long as you do not go over 55 mph then check engine light started flashinghard miss fire sh**. So I took it back and we moved plug then coil then injector but the miss fire did not move. This was cylinder 1 by the way. I left it overnight he called said it was a seeping head gasket fu**. Anyways I picked it up decided to drive it for a while and see what happens. To my amazement no problems runs great no water in oil not using water. Then transmission started acting up. $1300 later transmission is rebuilt but now at wide open throttle or with a load on it. It acts like it is skipping bad jumping and hesitating no check engine light though. So I had a friend use his scan tool and drove down the road all it would show is system to lean. I have looked at several threads on this and think maybe it might be a vacuum leak but was also wondering should I reset the Pcm because I know the mechanic did not after installing all of the new parts. Any help would be appreciated below are mods and engine info.
2005 f150 fx4 3v 5.4L
K&N cold air intake and high flow cat back exhaust
No tuner yet

 

Check your FPDM for corrosion.

See this thread for more information: https://www.f150forum.com/f4/fuel-pu...-yours-152908/

 

yeah I was going to check that also but I figured if it was going bad it would affect it from start and not just heavy accel

 

Ok so today I drove it again with a scan tool watching sensors. maf and O2 sensors showed fine but when I put a load on it climbing hill or trying to pass a car the fuel trim would drop to 0. Then it finally miss fired on cylinder 1 Again. Any suggestions I did find an exhaust leak but it was on the opposite bank as the misfire.



Really need some help. I'm getting tired of this money pit. I love my truck but it's just not fun to drive anymore.

 

FPDM... did you ever check it ??

 

Yes it looks a little rough but not terrible. I have ordered a new one should be here tomorrow.

 

A mechanic from the dealer ship said I need to pull valve cover and check rocker arms on that side to see if one fell off. Has any one seen this before and could this be causing these problems.

 

No...find a new Dealer