The check engine light had been turning on and off on my vehicle over the last several years, and it was diagnosed as a catalytic converter code by several other mechanics. I was told to not be concerned, as a new catalytic converter was expensive and I had no trouble passing emissions testing. The car seemed to be running well, however over the last last few years I noticed that it just didn't have the power/acceleration that it used to and fuel efficiency was extremely low. NW Auto Center was able to diagnose the actual issue (a knock sensor) and repaired the problem timely and at the quoted price. My check engine light has not turned back on, the acceleration has vastly improved and fuel efficiency is noticeably better. I highly recommend their services! Dan Camardella