Hey guys,

I just did my plugs in my 04 F150 5.4 The truck had a really bad miss, and I figured it was time for plugs. I broke all eight plugs which I expected as the plugs were in there since new and had 120 000 miles on them. Replaced with champion double platinum and I am not certain that was the best idea.

The truck is much better with the new plugs but still has a miss and a rough vibration. The truck seems to shake side to side at idle but smooths out during normal driving conditions. I have noticed that it seems to lack power intermittently if that makes any sense. Also, the check engine light was on for a while but I tracked that down to a broken wire in the evap system.

So I am thinking first step is to verify that the coils and boots were installed correctly. I have to see if we have the scope module for the Genisys at work. I am going to check for vacuum leaks as well. I just changed the fuel filter and no change.
Is there anything else I should look at? Would cam phasers cause a rough idle and intermittent loss of power?

Any ideas are much appreciated. I don't drive this truck every day so I can take it apart to diagnose it further

Thanks

 

The first thing that comes to my mind are the Champion plugs. Some have great success, while some report more problems after installation. Any possibility any one of the plugs was droped? This could cause a hairline crack in the ceramic resulting in a miss (experience speaking).

 

I was careful installing them. I did have one or two that slipped out of the socket and slid down in to the tube. I don't think that is enough to cause a crack. None were dropped on the ground

 

I have the same problem with my 2005 f150 FX4. I installed autolite plugs and now I got a p358 code. So I replaced all cops. no change. changed the cam sensors no change. replaced the cam sensor no change. I have been looking on line but no help. Iam retired and I do not want to take it to Ford.

 

P0358 is #8 coil primary circuit failure. Could be a loose connection at #8 coil, broken wire somewhere in the harness, bad PCM, or bad coil.

 

I checked all conections and wires, all seem OK. I put a plug tester on # 8 and it is getting spark. I replaced all Coils over plugs. I also checked for a intake air leak but did not find any.

 

My miss and vibration seemed to resolve itself. I am not sure if it was the fuel filter or maybe I put too much anti seize on the plugs. It still does seem to have a lack of power during hard accelerations. I can tell the engine is under load but it just doesn't seem to have its usual get up and go. I am thinking the catyletic converter may be starting to go. Now I just have to figure out a way to diagnose it