trucks been running rich

[93blackthunder]

Its run rich since i got it. Ive done everything i can think to do. full tune up, egr system is new. new o2 sensor new cat. all that was to pass emissions anyway. What else could it be. check engine light goes on at idle and off under throttle/above 1500 rpm.

 

[firefighter_2319]

you may wanna check your map sensor (manifold absolute pressure),while running you can unplug it and if it runs better with it unplugged then i would say that is your problem. the map sensor controls the way the engine runs as well. if it runs better i would have that checked just to make sure. hope that helps your problem

 

[93blackthunder]

Where's map sensor

 

[Horns]

The map sensor is on a bracket on the left side of the block. It has a vacuum tube that goes to the center of the back of the throttle body.

Another thing to look into would be the idle air control.