I had an engine light come on in my Buick Rendezvous and took it to Autozone for a check. It had a code that indicated it needed a tune-up. Greulichs said it needed a new tranny. If I wanted my vehicle back, I had to pay $1000 for "diagnostic" fees. They also stated that the vehicle was not running and I would have to tow it.
I let them fix the vehicle. Several weeks and several thousand dollars later, I received the vehicle back. It was not running as well as before they repaired it. The check engine light was still ON!
I called the company headquarters and they had me take the Buick to their Scottsdale location. The technician there told me I would have had better results if I wouldn't have had used parts installed. I had been charged a hefty amount for NEW PARTS at the Mesa shop! They changed the used parts for new parts, which again took several days. The check engine light came ON AGAIN on the way home.
I gave up and took it to a dealership. They found strange things like non-matching spark plug wires (Greulich's charged me $800 for a tuneup). The dealership felt the problem was a head gasket leak. Another $2000 and the check engine light no longer comes on. However, the vehicle no longer runs as smoothly as before it went into Greulich's and I am out between $7000 and $8000.
DO NOT go to Greulich's on Alma School.