80series turbo diesel shaking/hunting/idle prob

My parents have a similar issue with the Mazda 3 that they bought mid last year. They've had it back at the dealer a few times with no solution. It just started happenning one day after they'd had it for a few months. It doesn't seem to affect the power or drive of the car and it only seems to do it while it's in park. They thought initially that it was the engine mounts, maybe you could check that, but they turned out to be fine. I'll let you know if they ever work it out.

matt