We understand Mazda released a revised engine oil dipstick with a higher full mark. It also released revised software for the dpf operation that changed the way the self-cleaning function took place.

This is far from ideal use of a diesel with a DPF. Precautions you can take are to change the engine oil and filter every 7000 miles. Take the car on as many distance runs as you possibly can.

The sluggish performance and the erratic tachometer needle may not be related at all. That said, they could very well both be symptoms of the same problem. A lot of mechanics, when shown an erratic ...