After borrowing the Van to a friend for a short trip we begun to notice a significant loss of power and performance. Previous performance was satisfactory given the van's weight/aerodynamics.
Now the van cannot go over 75mph, pedal to the floor. The higher the speed, the less response you can get from acceleration.
Any idea where I should look first to tackle this problem?
Engine is a 3.9L V6 Magnum. It had some problems starting when cold - I had to give it gas to keep it from dying - that were solved after I cleaned-up the IAC and idle air passages. There are no error codes stored in the PCM.