I was trying to get rid of a nasty pinging probleme on my 97 3.4 T-100. I tried new filters, fuel injector cleaner, sea foam, resetting the computer, colder plugs. Nothing helped, the plugs hlped a little they were two steps cooler but, ended up loading the engine up at low RPM creating an off idle stumble. The ping would come on around 2300 rpm and last till about 3000rpm. It was worse in the heat and with the AC on. On 87 octane it would ping reguardless of temp or if the AC was on. 89 was a little better and premium got rid of it in all but the hottest weather with the AC on.
Well it bugged me to say the least. Pinging is the sound of an engine slowly destoying itself. I was almost ready to take it to the stealership when I stumbled upon the solution. I installed a set of JBA headers and crossover pipe. My thinking was the probleme lied in the engine management parameters. They weren't taking into acount a raise in compression due to carbon in the combustion chambers and on the bottom of the valves. When they modified the ECU (reflashed it) I wanted the headers to be on incase they threw off the computer even worse. Alot of thinking for nothing, Since the header install the pinging is gone?!
Hope this helps someone it only confused me even more, but as long as it doesn't ping I wont *****. <img src="/forums/images/graemlins/cheers.gif" alt="" />
P.S. The headers are great I noticed the power right away. I also get about 2 mpg better gas milage. The only draw back is they do produce more noise in the passenger compartment, kind of a rushing sound. Highly recomended <img src="/forums/images/graemlins/kewl.gif" alt="" />