When a CEL aka Check Engine Light is flashing, it it trying to get your attention! Flashing light indicates a more serious fault has been detected than if the light is steady on. Get your OBD codes scanned asap at a parts house, OBD means On Board Diagnostic, your car has a device that detects faults in sensors and other things, many other things, stores the faults and the parts house will scan them free. Write down the codes and bring them back here, and one of us will be happy to help you decide what to do next. I checked and it does have solid valve lifters, not hydraulic so they do need adjustment periodically, I hope he did it right. How many miles are on the car? Mechanics LOVE to change 02 sensors it is a high profit job for them. A less than reputable mechanic will change them even if not necessary because of that. But please..mileage? And do not delay getting the codes they will be "P" followed by four numbers for example P1234. Forget the jargon, forget the diagnosis a parts clerk gives you, just bring the codes
