This has a 5.8L engine, 180 thermostat and transgo shift kit.
It runs rich with the 180 stat but the mileage stayed the same.
Can you do a chip that will lean the engine out for 87 octane fuel?
Mileage not horsepower.
Thanks

 

Diablo with one program is what I want.

 

Sorry... but if you're looking for mileage its really not the solution you need. Its very difficult to accurately give you the air/fuel ratio you would need unless we had the truck in front of us on a dyno or at least a dyno pull made by you that includes an air/fuel ratio graph. The reason is "rich" is too broad a term for us to go by. I need to know how rich, exactly.

 

Unfortunaly black soot at the exhaust exit is the best I can give.
I will try and find an meter to check the exhaust gas for air/fuel ratio.