My buddy has a 2001 Cummins. At 60 mph it loses all power if you let off of the throttle. If you turn the key off and back on it is fine, until you get to 60 and let off the gas again. If you stay under 60 mph it drives great. Anyone know what it would be?

 

What if you dont let off the throttle? Does it keep goin?

 

Yes sir.

 

dirty MAP sensor, lift pump is bad, VP44 could be going out.