I got a 02 f150 super crew 4.6 i replaced the motor with a 08 i have a popping sound in front of the motor. Gets worst if you drive it you do hear slight back fire got p0171 new plugs coils changed the purge valve egr valve tps. Vehicle set for 7 years so it needs to relearn

 

Sat for seven years? Did you drain the fuel system or are you running on bad gas.

 

I think the 2002 was still using the EEC IV, but the newer engine is EEC V. May have calibration or sensor concerns. did you change the ECM also

 

EEC-IV went away around 95 or 96 in the F150 with the mandate for OBDII.

 

yes, that's correct. some of the 95's had both connectors IV was under the hood and V was under the dash

 

[QUOTE=Jimboy;7880221]Sat for seven years? Did you drain the fuel system or are you running on bad gas.[/QUOTi did drain and removed all debris