I am hearing a "tingy' "tingy" "tingy" sound when accelerating..it is not evident at cruise because of increase in frequincy of the sound coupled with road noise. During cruise however if I go to neutral and rev the engine I do not detect the sound. It seems to be more evident when in gear (auto Tranny here) . Think of a bicycle wheel with the spokes and holding ,lets say a dinner knife against the spokes while the wheel is turning...thats what it sounds like.I do not think the engine is pinging because at idle first thing in the morning I hear a slight sound similar to what I described and when I lay under the car it seems to be coming from the oil pan/transmission/engine area. Also if I reverse fast and coast to a stop I can hear the sound even louder...strange but true...it sounds like two rusty turning parts touching each other ...sort of like a ..crenk..crenk..crenk...sound. Any suggestions?