I have a ping on acceleration that gets more pronounced with higher ambient temperature. I have a 6.0l vortec, in a 1500HD Sierra Crew cab. I have replaced all 4 O2 sensors, MAP, TPS, knock sensor, intake gasket, air temp sensor, & MAF. It has 109,000 miles.automatic, & has 3.73 rear gears. I get a P0140 and P0160 codes after taking it down the road at 45-50 miles per hour. If I only use about 1/4 throttle it doesn't ping unless it's above a 100 degrees outside. (It IS Arizona after all). Help!!! ---------- Post added at 04:01 AM ---------- Previous post was at 03:18 AM ---------- I almost forgot, sometimes it "stumbles" when I pull away from a stop.