Hello everyone,

I have a 2007 XK and the engine knocks. I've taken it to the dealer 4 times and have finally sent Jaguar a Final Repair Attempt Notice. When I've taken it to the dealer, I've had the service manager ride with me twice and showed him the problem. Each time the dealership says they cannot find any problem with the timing and suggest that I must not be using the right gas (they've said the gas was dirty or thin in the past). I've started using different gas stations and saving the receipts to show them at the final repair attempt. I've poked around the web to learn more about engine knock, and what I've seen is pretty grim. I'm hoping some of the readers of this forum can give me some perspective on engine knock and its potential consequences.

First, how much engine knock is out of the ordinary? The owner's manual says that light engine knock under a load or on acceleration is normal. The service manager described my engine knock as light, though it seems pretty loud to me. It knocks every day consistently, which doesn't seem right. Does anyone else's engine knock? Everyday?

Second, would a properly functioning knock sensor correct the problem before I would even notice it? The service manager suggested that the knocking only lasts for a few seconds at a time because the knock sensor is correcting the problem. To me, if it's still knocking at every stop light and at every acceleration, the knock sensor could be vastly improved.

Third, how bad is this problem? Wikipedia suggests that the only thing that could be worse is to run the engine out of oil.

Thanks everyone for reading this--I know hearing about someone else's car problems isn't very exciting, but any advice on this would be greatly appreciated.