i have a 2009 V-8 Tahoe LT with just at 90,000 miles and the stability track and check engine light and reduce power occurred to my wife driving home. Ive been searching the internet and noticed this is possibly the issue with throttle position sensor. I've seen several posts with 5 yr warranty which mine has passed. Somewhere I've seen a letter was sent to others saying 20 year 120,000 mile warranty. If this is true where can I get that and possibly get this fixed for less or no costs?