Bought deisel truck for camper and boat. this truck goes over mountain passes like the load isn't there, 15,000lbs. I bought an aftermarket engine program to increase performance, and with this chip I get 20mpg empty, 15mpg with boat or camper, 13mpg with boat and camper. Programer takes 5 minutes and allows me to program for specific loads or to put it back to stock settings, recommend this. There has not been 1 problem with truck and have already put on 12,000 miles in the first 4 months. Very happy customer.