I agree, testing is a good idea. The reason I was suggesting the tune first is it's very likely the truck is already tuned. We have no idea what kind of tune or how agressive the timing is. It might be a very bad tune to be towing with, so my thought process was, get the tune set up for Kevin's needs, and see how the truck responds. One other thing I thought of was some sort of boost fooler device, although I the that would set underboost codes sooner than overboost. But just another thing to keep in mind.

James Kuhns
Owner/Technician
Auto Tech Solutions
Chatham, New York, USA