So i decided to rebuild my 2002 manual maxima i swap out the motor since it was starting to smoke add new ngk spark plug and oem coils replace all 4 o2 sensor and the maf sensor new clutch and flywheel and headers when it can to start the car it started find then it start idling rough and smelled alot like gas and it would backfire after driving it theres a loss in power the engine is fine do you guys have any idea what it can be the car is running super rich do i have to reprogram the ecu

 

Be sure the Injectors are not leaking... You mentioned you replaced the Maf. Have a Look at its value on a scan tool or swap your old one back for testing purposes.

 

The injectors are good i even swapped them out to my old ones the maf i replace cause it wouldn't rev pass 4000 rpm should i take to the dealership and have them flush the ecu

 

I also have an 02 with a 6 speed (310,000 miles ) and an issue I was having was bad coil connectors.

 

You're misfiring. That's why it smells like raw fuel.