heys guys whats up im new to this site so ur help would b greatfull i have an 04 f150 fx4 newer body style with the 5.4 3v it has an air intake, throttle body spacer, headers and full mbrp exhaust. my cheack engine light came on and i pulled an p0171 and p0174 codes bank 1 and 2 lean people r telling me its a vac leak sum where but where would i start to look ne ideas would help.

 

Do you have a tuner? There are issues with CAI causing lean conditions on the 5.4.