Hi fella's, I'm gearing up to do the mod to my wife's suburban(98). I've been rather hesitant to jump in as it seems gains are rare with these beasts and if I screw it up somehow I may get reminded of it more than I may like to. I'm wondering if I should record fuel trims pre and post groove at idle or under load? Also a little fuzzy on exactly how to isolate climate control system without rendering it inoperable. Thanks, Jeff in Wenatchee

Hi Jeff and Welcome!

Don't hesitate on the Suburban. As far as data/information, if you can get pre-mod engine, manifold, cat converter, exh temps with an infrared thermometer, that would be great. Fuel trim and scan tool data would also be helpfull. Then do the groove, cap off the pcv and redirect it to a pre-throttle body position. Check for vacuum leaks - I believe the '98 vintage used vac operated servos for HVAC control. But DO THE MOD and please report your pre and post information. We are here to help.

Call me if you have questions - I not only play a mechanic on TV but also in real life!
My # is 1-231-203-3072

Scott Castleberg
Pellston, MI
Gadgetman Michigan