Hello -
New here, just introduced myself in the new people section...

I have 2004 5.4l 3V (new body style) truck.
I had detected some type of rough idle several weeks ago after my truck was sitting idle for long time during the holidays. After a few days of driving it like that finally a CEL came on and I had AutoZone read the codes, I got 304 and 316.
With that I purchased an Accel COP and change it out. To do this, on #4, you have to remove the battery and the PCM out of the way. After the COP change it appeared the truck was running better but after driving awhile the CEL came back on and also started running like crap again (at idle).
I dont really notice any problems when not at idle but I could just be numb to it at highway speeds.

So I then purchase new plugs, champ 515, and changed out all the plugs. Only broke #2.

After the plug change I drove the truck about 100 miles, mostly highway and some city miles, the truck started running bad again and the CEL back on with those same codes to cylinder #4.

I purchased my one ODB2 reader at this point.
After the east coast blizzard was over and able to get to my truck I wanted to change/check the injectors.
I removed the rail and pulled #4 injector, I connected it to my battery (out of truck) and can hear it working, also I sprayed some cleaner through it while it was open and it sprays, so I didnt change it. I did swap it was #1 though. Truck runs the same and still the same codes with #4 cylinder.
I then moved the COP #4 and #2, still runs the same and same codes.

So at #4 cylinder I have had a new COP, #2's COP, #1's injector. I have no other codes.
I have used FORScan SW to read codes and monitor the trucks PIDs (so many, I dont know which ones to monitor), but there are no errors on injectors or anything that I can find. If I disconnect a COP the truck runs the same no matter which one I disconnect (thats odd) but it also gives me a specific code error when they are disconnected.

I have searched and searched the internet for answers and read through many forum threads. It seems this problem is very common and the only thing not common is the fix.

I would think the VCT would be more codes or change up the codes, same with fuel filter. Not that I am against changing the filter for peace of mind.

My biggest problem working on vehicles is getting the connectors apart without breaking them. Already broke the locks on the two connectors at the i guess throttle body (two connectors on the driver side) when removing it. Tried the fuel filter and that quick disconnect isnt all that quick, I cant seem to get it unlocked...

Any help is good help.

 

Have you done a compression test on #4?

 

I have not. I couldn't find anywhere that had 16mm fitting to check it this past weekend. Its something that needs to be done. I just dropped the truck off at a mechanic, I should have asked if the compression test was in their 120 diagnostic fee...
Hopping for some good new from them though.

 

truck was in the shop for 2 days. They verified all my work on the cops, injectors and plugs is all good. Did an injector test, idk, where they bypass the pcm and fire the injectors testing the % spray, checked good. Compression was checke at 160lbs.
Still not sure what's happening.
Codes were reset there and currently it's still in the drive cycle so no codes are up yet. I can feel the misfire happening sometimes. FORScan software is currently not showing a misfire.
Maybe PCM problem. Not sure if I should change the O2 sensor, crank position sensor, VCT solenoid and then if that don't work take it to Ford to test the PCM or take to Ford before changing those parts. All those parts should cause misfire in more cylinders and make others codes occur.