Nissan Repair: rich condition with no power, mass airflow meter, haynes manual

Question
I have a 1987 hardbody with a 2.4 eng. and it starts fine but smells of gas. with no load it will rev with no problem,but while driving it will blow black smoke sputter and not do more than 20mph by pumpping peadle. i have replaced the injectors ,pressure regulator. please give me direction.

Answer
Eric,

No codes?  Well, check the fuel pressure first and if the pressure is fine check the throttle position switch to make sure it is reading correctly.  Get a Haynes Manual for the specifics on the rsistance the circuit is supposed to be reading.  If this is correct check to make sure the coil is firing correctly.  Lastly, a bad mass airflow meter will give you this problem too.  I am giving you things to check from cheapest to most expensive as well as easiest to most difficult.  If you need more email me back.