P0174 2001 Ford F150 -

Question

2001 F-150 4.2 v6 engine sluggish, popping in cylinder, drop in rpm when stopped with air on, it shudders around 35 mph then again around 50, code P0174. Sometimes P0171. I have changed EGR, MAF, Ran fuel injector cleaner (seafoam) Verified coil pack is working. No vacuum leaks. Next I am replacing fuel filter and fuel injectors. New (crate) engine with only 36k miles. I remanufactured the heads. All other parts are new. Any ideas?

Answer 1

Hi there,

I would check the fuel pressure. With all that you have done and considering it's affecting both banks on the engine it's quite possible the fuel pressure is low. I would not replace the fuel injectors to resolve these codes.