Gayle

I have a 2007 Ford f150 5.4 3v engine, we have replaced plugs, coils, pcm, O2 sensors, and I still have no passing power.. The vehilce runs great up to trying to pass a vehicle, then it just bog downs and has a little back fire. I have a lot of money invested in this vehicle and I sure could use some help. We are not getting any codes.

BOOMER-Red

iTrader: (1)

I had an '05 FX4 w. 5.4L and I had the same problem until I got an Edge tuner. With the Edge I had no problems passing, before, I would punch the gas pedal and the truck would roar but not move but would gradualy get the job done.
The Edge also solved a mpg problem as well, no matter how I drove; hwy or city it would only get 12 mpg. After Edge I was getting 13-15 city and 17-20 hwy.

obusnizzle

www.vmptuning.com

JimFX4

You did not mention fuel filter. A clogged fuel filter can seriously bog an engine down.

BOOMER-Red

iTrader: (1)

Thats a good point. I think they are supposed to be changed every 15,000 miles. At least that is what my '05 manual stated.
And it is very easy to do.

waterboyjlw

I had a the same problem on my F250 5.4L 2V, did the plugs, coils, both o2 senors, Throttle position sensor, Had the cats checked for flow, fuel, filter, and a couple other things too. What finally fixed the incredibly weak power (and occasional miss under hard acceleration) was ...a rebuilt set of fuel injectors that I bought on E-bay for about $100. Seeing as you've already done most of the things I did, it's a small price to pay to rule them out. Bonus for me was a 2 mpg increase right before a 4200 mile trip, they paid for themselves immediately.

Gayle

Yes we changed the fuel fitler and injectors went back with all motorcraft parts. changed the coil pack, we are thinking it has something to do with the fuel system not the engine any thoughs?

2000xl_toronto

have you actually checked the fuel pressure with a guage? You could have a faulty fuel pressure regulator

waterboyjlw

+1

If that isn't it....it's time to start checking cylinder compression