Well my truck (or bad luck charm) is doing something new. If shes hot and Im running hard (say down the freeway at 70) and then get off at a ramp and stop at the light and then excelerate hard it Pings. It sounds like a gasser and pings for a few seconds. It will only do it when hot and only if running fast and then stop/go.

Any ideas?

It does it with normal #2 and bio diesel as well.

My truck also has (until the bio) had the lopey idle and rough idle.

no power adder?