I have a 93 Nelson tune and gained 2-3 MPG would I get anymore with a straight fuel mileage tune? I lost the 2-3 MPG since I installed my MBRP 2.5 dual exhaust. I am going to send back for recalibration, and wanted to know if I could get more MPG with a fuel mileage tune?

With diesel going up, I pulled my gasser out of storage. Just headers,exhaust, and air filter. No tune. Took it to Vegas a month ago. 15mpg at 65 cruise control. Lancaster to Vegas, ONE tank, 26 gals, and had some left to cruise round a whole day with.
That was hand calculated!

any other info on this? my truck is only getting 9 MPG. 2001 2500hd CC 6.0 with 4l80. 4inch lift with 33-13.5 18 MTZ's