For some reason I can?t get any more advance of out my ecm past 40 degrees. I know you are thinking wtf for? Well when I tune trucks I can advance the timing more than 40 degrees, and it adds a little more mpg because it makes a little more tq and it requires less throttle input at cruise. I can force it with my scanner and it does exactly that, it helps, but I cannot force it to do it on the tune. What gives? Something I?m missing somewhere? Maybe a workaround? I have a low compression 5.3 in a gto and I?m trying to get a little better mpg out of it. 2004 year model of that matters, originally an ls1 car.