My ford F150 2001 XLT 4.6L at times will loose power while excelerating kind of like bogging down as if it wants to shut down. I have replaced the fuel filter the air filter and still the darn thing still is bogging down. The odd thing is is that when I took it to a shop they said there was nothing wrong with it. Oh and when I was at a stop light I started to excelerate and I had to apply the brakes quickly and as soon as I did that the truck started to rev up and down over and over again it stopped when I gave it some gas.

Replace the spark plugs with the exact Motorcraft plugs that came in the truck, if they have not been changed in 50,000 miles.