Had this truck a few years now, and it has always had a slight miss/hesitation and maybe a few codes. The timing chain skipped a tooth and the truck was down for about a year. I have 4 other trucks, so it wasn't a big deal. I finally had time to put a new oil pump, chains, guides, tensioners, phasers etc. The truck actually runs very well and quiet. But, now misses far more than I remember it doing.

When driving in town constant at 25-30 mph occasionally it will loose power for a brief moment(<1 second) and then be fine, the security light on the dash turns on for a few seconds.

It drives at 55-65 just fine, unless I am going up a hill or something else increasing the load.

2004 5.4 3v 2wd
CEL-
P0453 (fuel tank pressure issue)
P0351 (ignition coil a primary/secondary circuit malfunction)
P0356 (ignition coil f primary/secondary circuit malfunction)

The coil packs are new, and I have injectors on order. But, any thoughts or ideas would be much appreciated.

Also found this thing on the back of the motor, it connects to the fuel rail on the drivers side. No idea where it should go. I looked on my other trucks. But my other 04-4wd has a box by the battery it connects to, but mine doesn't have any of that stuff. And my 08 doesn't have anything like this at all.





And a pix of the truck in question. Thanks again!

 

That's The Vacuum line for the front diff, uses engine vacuum to engage the hubs when shifted to 4 hi/lo your truck is 2wd so its capped

 

Thank you sir! That's what I had figured. But also wondered why Ford would go to the trouble of fitting that line onto 2wd trucks and just leaving it hanging.