ok....engine shakes and i'm pretty sure its a misfire....still has good pep just shakes like it running on 7 cyl....have replaced plugs, wires, cap, rotor, all 8 fuel injectors, intake gasket....even reset computer to factory defaults.....has superchip.....nothing worked....will do compression test when its not 20 below out....weird thing is that pulling a trailer i can feel it shake and then not....then start shaking again..... so i dont think its a motor issue for some reason......fuel injection wire harness? cam sensor? pretty sure it cant be crank....unpluged it and it wouldn't start....bad computer? don't think it has to do with fuel pressure reg, pump or filter.....fires up great cold or hot.....just has a shake to it.....noticed its really bad on the hwy with the lockout on the 4l80e kicked in.....anyway could it be the transmission? not driveshaft.....shakes when at idle in park pr drive.....thanks for any info....im starting to give up.....no coolant in oil/ exhaust, light oil consumption 180k