My 2003 Camry with 30k miles makes a pinging/knocking type noise only at about 42 mph and on hills &more as it warms up.I have taken it in to the dealer to have them tell me change the gas I use . after using only chevron 92 octane for 15 tank fulls and the use of techron and red line fuel system cleaners, the sound is the same. I returned to the dealer to have them tell me about a tech bulletin that had sounds coming from a defective baffel in the intake manifold. I had the intake manifold replaced and still have the same sound. the service manager told me that the egr had been checked and the car should not be knocking and pinging. Any similar situations that might help me in my 4th visit to have this problem corrected would be greatlyappreciated.