Has anyone out there reprogramed a computer or installed one of the economy chips and with what results. My 99 suburban 4WD is the sickest running thing I have owned since my '77 Chrysler Cordoba, not to mention the pitiful fuel economy. I just spent the day on the phone picking brains about camshafts, headers, MSD ignitions, K&N filters etc. and have come to the conclusion that no one out there is certain of anything. Has anyone tweaked and peaked one of these things with positive results? I suspect that I am not the only one who would like to know. The Grump