Hello, I have a 08 f150 with 100000miles and just recently it started to bog down under load, I have changed plugs (with oem) o2 sensors (oem)fuel filter, cops, maf,

I have ran 4 tanks of gas threw it now from place i know the fuel is good, an still acts weird. I can be goin down the road and it seems like i hit a head wind when i pull trailor an when i start giving more throttle it does nothing till i hit down shift trigger.

Any ideas would be appreciated.

 

I take it you have no code. Could be the throttlebody sticking. My son had the same problem on his 2006 5.4. It finally threw a code and it was indeed the throttle body hanging up and not reacting to the pedal action. It has been an issue on some 5.4's especially in cold climates which I don't believe you reside in but it may not be a true factor.

 

Thanks for reply, but i tested it today and was okay. So i put my stock tune and airbox back on and now the truck runs fine.

Why would all the sudden truck start acting like its running out of fuel, but with stock tune run fine?

Im at a lost