5 /5 John McInnis: My go to dependable mechanic diagnosed our 2003 Miata check engine light caused by a misfire and said a valve leak might be the problem. He said he could not work on it and suggested two other local shops. I tried each and neither could do the job, one saying the reason is there are few automotive machine shops left that can grind valves or do deep engine work. It took a while to find BOSCH AUTOMOTIVE in Petaluma to take on the job. There was a three week wait and another three weeks in the busy garage to complete the work, but entirely worth it. Ernesto discovered multiple valves burnt and in need of replacement. Our wonderful little ride is back to life in tiptop shape, quieter, smoother than in a long time; the pesky check engine light vanquished.