Reviewed By Howard M (ENTERPRISE, AL) Reviewed for a 2005 GMC Sierra —12/13/2013 6:07 AM
I purchased the Bully Dog to increase fuel economy on my 6.6 GMC diesel. At first it didn't seem to make any difference so I called their tech support (they were great!) and discovered I did not have the settings correct. Since then I have seen an improvement on mileage and I love the different feel in the over all performance. I am glad I made the purchase!