V8 5.7 gas engine.

Had the following codes-mass air flow sensor, MAP sensor, and intake temperatur sensor.

Started by replacing the map sensor and intake temp sensor. Gave a complete tune up- plugs, wires, distributer cap, rotor, and changed the fuel filter. Cleaned the mass air flow sensor.

Truck still ran rough. Dies when you start it unless you keep foot on gas. When you shift from park, you have to go straight to neutral and let the motor catch up with itself. While driving, it will bog down slightly.

Had the mass air flow sensor tested, and it tested high out of range. Had vacuum guages hooked up and it shows no vacuum leak. Fuel pressure also tested normal. Replaced the mass air flow sensor and still have the same problems.

If the air intake sensor is unplugged, it still runs rough, but better than with it plugged in and it is actually driveable.

PCM is giving proper voltage to the mass air flow sensor.

 

Have You Checked EGR?

 

How do you check that? He pulled the vacuum line off the top of it, and it is sucking real good and the motor starts sputtering.

 

Not sure if this makes any differance but it is throttle body injected and does NOT have spider injection