I have a 2000 Ford F-350, before the chip I was getting 16 mpg with no load. Now I am getting 19.6. Towing my 4000 lb boat my mileage is 15.9-16.5. I also installed a 4 inch exhast system to aleveate back pressure and heat build up. Almost everyone I know that has a powerstroke has installed chips, and I have never heard of a problem yet. Actually, it isnt even a chip, you get a programer that plugs in under the dash to a existing port. 5 minutes later after following the prompts on the programmer, you have 80 horsepower more. I never even opened the hood. When I went in for warranty work ( an
oil leak), I just reprogrammed it to the factory specs. Summary? GET IT!