Thanks for adding me to your Forum. Although I worked as a technician for over 20 years, 20 years ago I am new to programing or modifying a PCM. Hopefully I can learn a lot as I do a 411 computer swap into my 1999 L31 Tahoe.

I am not trying to build a hot rod. I am trying to fine tune this new crate motor to reach its full potential as a tow vehicle. I have already deleted the cats, modified the mass air flow and the throttle body. I have also put 265/70-16s on it. I started out getting 12.8 to 13.6 mpg. I am not getting 16.5 to 17.5 mpg.

I plan on doing a cam swap (GM 14097395) with roller tip rockers. My Tahoe turns 1750 rpms at 65 mph. I rarely turn the engine over 2500 rpms.

Thanks again