1997 Honda Accord mileage: 104,000. I have had trouble with the engine pinging since day one. I have had a rebuilt carburetor put in, the timing checked constantly, the mixture adjusted and nothing helps. It pings a lot under load such as going up a hill or accelerating quickly. I have had a couple different mechanics look at it, but they couldn't find a problem. Any suggestions you can give me are greatly appreciated. Thank you for your time.