Hello all, I have a 99 GMC 4.8L 5M truck that I have disabled the EGR, plugged the manifold and also bumped the idle rpm up a bit, removed the low OEM speed limiter and disabled rear 02s. I am getting abysmal mpg now with the egr disabled. Is there any way someone from here can get me dialed in? I have a data log of a 6 mile driving loop, cruising, acceleration and WOT all mixed in. Any help and guidance much appreciated!