I have a 98 c5 with 408 mild cam and 40lb injectors. Did a mail order tune and the car ran decent. Decided to get a dyno tune and now if I go wot it dies and backfires. The tuner put the original tune back in and same thing happens. The afr drops to 10 once you wot. The afr is real erratic when driving normal jumps to 17 and goes straight to 10. I am getting a p1133 code o2 bank1 sensor 1. Did change the crank senor and checked for any exhaust and vacuum leaks. Not sure what to look for if its a tune issue or mechanical. I attached a scan log and tune file. I appreciate any help. Thanks
cutt off scan.hpl 98 c5 408.hpt