I had an older GMC truck with a large big block gas guzzling V8. Before selling it I had to get it to pass smog. First, I took it to a Test - Only shop. It failed miserably and the suggestions from the technician didn't help it pass. Next, I took it to a nearby shop and after another $300, and a bunch of new parts that I still doubt were necessary to replace, the results were less than favorable. After a few weeks of frustration, I remembered someone telling me about the difference between a smog only test center and a gold shield test center. Smog only test centers do just that - Smog only. They are not authorized to do ANY types of repairs on your vehicle to get it to pass. The Gold Shield smog centers are the Full Service version of the Smog testers. I found Glenmoor Auto Repair when searching for this kind of Smog tester. I called Gary and although he had a full schedule was able to fit me in. It turns out the truck needed a new catalytic converter and it passed with flying colors the very same day. The cost was reasonable and I would recommend anyone with complicated smog issues or older vehicles to go see Gary first to save them the weeks of frustration that I went through.Bottom line: take your vehicle to Gary and get it fixed right the first time!