Hello! I have a 99 Ford F-150 4x4 with a 5.4 with less than 40k on this motor. I had 198k on the last one before spark plug issues. If I am going slow (still in 1st gear) and accelerate hard, the truck will run right up to about 5 grand and then when the truck shifts, it falls flat on its face and then slowly accelerates again. I don't know if the truck is skipping second gear and going straight to third and then dropping back to second. I am tired of getting out run by bowties. I also have a K&N cold air kit, flowmaster cat back kit, and hypertech programmer. this truck should scream down the road. this problem has been going on for a very long time. I also am running 285/70/17 tires with the original 3.73 gears.

thank you for your assistance.
Mark

 

Clogged fuel filter resulting in low fuel pressure? Good luck!

 

The truck runs hard all the way up to 5 grand, so I wouldn't think it would be a fuel supply issue. Doesn't happen everytime. When it peaks rpm and shifts to second, I think its missing second and goes to third and then back to second real quick.

 

The only way to be sure is to put a pressure gage on it. When was the last time that you checked the transmission fluid for proper color and smell? Might be time for a transmission flush and fill. Good luck!