My best advice is to find a different repair shop. A mechanic who tells you they don’t know what’s wrong or advises you to replace an engine without identifying the problem indicates to me that they don’t know how to fix it. Find a reputable repair shop: ask your friends for recommendations or choose one of AAA’s Approved Auto Repair facilities. (Our AARs are vetted and meet strict quality standards.) One of the best relationships you can have is with a trusted auto technician, and it’s worth the effort to find one in your neighborhood.