It seems like everybody has a different method to decarbonize an engine. I've personally tried Seafoam and ATF through the Intake. Both to no avail. I took one of my older 22re's to a local shop that did an I.V. induction and this seemed to cure the problem but the mechanic also told me that he retarded the timing a little. My new(to me) 94 with 22re pings and I'd like to CURE this myself without taking the timing back from 5 degrees since I don't have any H.P. to spare. Please post your pinging remedies but ONLY if they absolutely CURED your problem.