Okay here's the deal i have a 2006 Pontiac Grand Prix GT with L32 and 92,000...so, the car runs and drives like a dream, other than annoying suspension creaky bushings...but, i've noticed rather horrifyingly that if i do a high speed pull, by the time i hit 120 it hauls getting there, and at that point it seems like it hits a brick wall while the DIC still shows "full boost", the ses begins to flash, and i stop and glowing front and rear exhaust manifolds, and while the Cat is not glowing the piping directly before and after are glowing as well. i did capture a code which turned out to be a misfire in cylinder 1, but i don't always get that..... Do we think its the cat? if so i'll definitely be doing a downpipe w/out cat blah blah......I don't have a scan gauge handy and am just trying to detail it for you guys...this happens whether i run Stock Platinum AC Delco or Autolite 605 (one-heat range colder) Coppers... This car now has an Overkill tune which i adore, but the problem still persists...Under wide open throttle, like i said its fine until almost 120mph...
