Since I've installed the roller rockers and the loudmouth my gas mileage has dropped considerably and I was curious if a custom tune would tweak it up so my gas mileage would improve some. Near as I can figure it lost around 2.5 mpg.

 

You probably should start with the basics. I would check plugs, wires, air filter first. If all those are kosher, then bring it in for a dyno run with wideband O2 support. You may be running richer than you think.

 

I agree, everything that you have done should not affect your gas milage. Check the plugs/wires/ fuel filter all that crap b/c you haven't done enough for custon tuning.

 

Maybe its the foot mod! LOL I know when I installed the headers or when i have the cutout open my gas mileage drops.