I have an 04 f150 (newer body style) 5.4 fx4 with weapon x c.o.p.'s, true dual exhaust and only 46,000 miles in which at idle it seems to idle smooth then seems to miss every once in a while and also when I idle it up to about 2000rpm it misses even more but it's even more obvious I can actually hear the exhaust sputter a bit when it misses.
Also when I rev it and hold it to 2000 rpm or near it in some spots it revs up and down like it misses then it doesn't and it revs back up then it misses some more and I can watch the tach pulse a few hundred rpm.
The other day I was playing with the throttle and I just tapped it (to where the sensors just picked it up) and the rpm dropped almost killing the engine, so I did it again and I can actually kill the engine if I hit the right spot by barely tapping the gas pedal.

At first I was thinking it was ignition coils so I put the street performance weapon x coil on plugs (the ones they say don't need a tune cause they're basically a stock spark) but it didn't go away so then I was thinking fuel injectors after reading around with an obvious intermittent miss at 2000rpm but now I'm almost wondering if this could be my throttle positioning sensor or something fly by wire?

I'm kinda lost and don't want to start dropping money on parts that don't solve the issue unless this is normal in some ford 5.4s... this truck has been babied for the most part and the engine is running strong (I got the edge evo which doesn't seem to effect the miss fire, besides the fact that when I put it in performance tune it got worse performance than in the tow tune) but when I tune it to tow I still get an average of 14.5 to 15.5 second quarter miles minus the fly by wire response which is almost always a half a second to a second.

I'm just hoping someone had the same issue or someone can lead me in a certain direction to help me out.
Thanks in advance for your input!

 

Haha did I type too much? Or has anyone had a similar problem?

 

When was the fuel filter changed and it won't hurt to clean the MAF.

 

I just changed the filter about 10,000 highway miles ago, and I'll try the maf tomorrow. I now feel it through the transmission at certain rpms and I was off it's at about 1200 rpms where it's the worst

 

Still haven't gotten to the maf sensor yet but I did run into this on another site which sounds more like what my issues are.

Make : FORD Model : F150 Year : 2004
Manufacturer : FORD MOTOR COMPANY
Service Bulletin Num : 05417 Date of Bulletin: MAR 07, 2005
NHTSA Item Number: 10014666
Component: ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE [EGR VALVE]
Summary:
INTERMITTENT ROUGH IDLE - NON-COMMANDED EGR [EXHAUST GAS RECIRCULATION VALVE) FLOW. *TT


Still going to clean the maf sensor but it doesn't seem erratic when I check its reading with my edge evo and no it's not my evo I've tuned it back to stock more than once although the evo brings the vibration out a little more but not much.

 

Pull codes and see what faults are occurring.

 

I cleaned the MAF on my 04 F150 4.6 w/electronic throttle. And everything seems to work fine, idle is approx 1100 according to the RPM in truck.

Now when I turn on my A/C the idle drops to 550 or so and then the engine light goes on.

Turning on the A/C this time of the year...I know I get hot easy.

What should I be looking at? Dirty throttle, butterfly?

 

That's the problem there aren't any codes. I'm actually starting to wonder if this is just how these trucks run cause I just changed out the injectors and well I've got more power but it still seems to have the rough idle/dead spots in the rpm in neutral just not as bad as before.