I just installed the 87 tune from the Diablo Sport and now it pings at high rpms from 1-2 2-3 for a few secs. I have a 01 4.8 with cat back exhaust, air intake, de-screen maf, and I just changed the plugs and wires. I put ngk and msd wires. It didnt have this before the tune. Can the tune be to agressive for reg. gas. I just filled up with 89 to see if it makes a diff. Any ideas. THANKS