BROWNINGFX4

i have a 2004 f150 5.4L v8 fx4 subercab it has about 130,000 miles on it, when i am at a stop i feel a moderate vibration sometimes it will come in soft and be medium, when its at its highest you can feel it in your body but when i take off it stops vibrating, can anyone tell me what this is? im a college student and just had a baby so i dont want it to become a worse problem. thanks

rtg143

Does it feel like an engine missfire? Maybe somthing is against the engine and body.

Ruprecht

Does it feel like your engine thinks it's a diesel? Has your fuel mileage dropped into the single digits? Open the hood and get your ear near the valve cover, is there knocking? If the answer to these questions was "yeah, I think so", then do a search on this site for "cam phasers".
I hope your answer was "No, not at all".

tygr1

Geeeez, you guys quit scaring the kid.

Have the plugs ever been changed in your truck?

Rep.OF.Georgia

hi,
i have 2004 f150 V8 4.6 XLT Triton, truck has 63.xxx miles on it, i have exact same problem, engine vibrates some time it is soft some time you can feel in your body all this vibrations. first thing i thought was engine was misfiring, so i replaced all coils, spark plugs and boots. but result was same, same vibration. i have everything stuck, nothing aftermarket. i have no idea what to do but as i see it common problem with this trucks. if anyone has any thoughts, any ideas please let me know. thanks

xJimbos

other than plugs it could be the:
ignition coil(s)
injector(s)
MAF, yeah check your MAF cause mine was melted when I bought my truck
fuel pump/pressure regulator
check your wiring harness ALL OVER, everywhere. See if you find any anomalies, esp. ones connecting to sensors
clean your throttle body?
intake manifold leak or leak somewhere after the MAF but before the intake manifold

All of this stuff can be done at home for relatively cheap. Go buy a hayes manuel.