FordTech413

Howdy, today while I was driving I noticed a lack of acceleration or a lag in throttle response while first starting up an incline then, once about half way up the incline I realized the truck(an 04 f150 lariat 5.4L) began to buck and then the more I applied the gas to try to climb the hill the more my truck bucked and trailer hitched. Once I got the top of the hill and the road straightened out... I punched the throttle and the truck hauled *** with absolutely NO lag and then at the light up the road the idle was perfect and smooth. So therefore the problem is only in going up hill, I assume that the problem maybe be the ignition coils seeing as though my trucks symptoms differ from those of a failing cam phaser. Recently I replaced the alternator, serpentine belt, oil, oil filter and fuel filter. Anyone who could help me out it will be GREATLY APPRECTIATED!!

powerranger262

Clean MAF and Throttle body. Change fuel filter, and check out your fuel pump driver module. How many miles on the truck?

FordTech413

Thanks!, I forgot to mention that I did clean the MAF and throttle body. I will defiantly check that out. The truck has 121,000 miles on it.

jamie930

121k miles on the plugs?

If so change the plugs and COP boots

Trtodd75

My truck was doing the same thing, changed plugs and fuel filter and it went away!

FordTech413

Most likely, I bought the truck about 3 Months ago from a private seller and don't have any service records. Thanks, the only problem now is coming up with the money. hahaha

FordTech413

I glad im not the only one and that there is a fix. Did you use motorcraft plugs? Thanks by the way!

Trtodd75

Yeah I did, luckily none broke coming out! So it want too bad!

FordTech413

Yeah, I think that's what I am probably going to use. Wow, you usually don't hear that about any of the ford modular engines especially the 5.4 you must be either really good at working on engines or really lucky!

mmdutcher

Same thing happened to me. I changed the plugs and the issue went away.

Good luck.