As a longtime lurker, I have received tons of knowledge from members that benefited me greatly as regards my 1999 F-150. I come here again asking for help regarding a perplexing issue that continues to bedevil me. The truck has about 165,000 miles on it and I recently replaced the fuel pump assembly. I diagnosed this based on the engine not starting and I was unable to hear the fuel pump energize when turning the key to start. I did check the switch in the kick panel as well as the fuses/relays first. Replaced the pump assembly as well as the fuel filter just to be on the safe side. Turned the key and heard the fuel pump energize. The truck starts but runs rough. It has also developed a knocking that seems to increase with rpm. Not exactly sure where it is coming from, but it seems to be on the driver's side of the engine. The truck also has low power. I am afraid to drive it and also don't have any codes to tell you. The local Advance would not loan a reader. Anyone have some things I can check or should I just bite the bullet and have it towed to the shop?

Many thanks for your help. Now and in the past.

 

Should have started with a fuel pressure gauge. I'd still get one just to be sure..

 

The knocking is indicative of another problem. You need to do a lot of checking and ruling things out. Fuel pressure would be a start. Maybe a compression check.

 

Getting a pressure gauge. Will post results as soon as I can. Thanks for the help so far.

 

X intake vacuum.