Glad you figured out what was wrong. You're lucky the diagnosis was only $60 or whatever... diagnosis with a GM Scanner is $100.
And another thing, you screwed up with what you told them. Here's how it should have went. When they told you such and such part was bad, the cost, you tell them "thank you. I will come pick the car up today and I will definitely be back to get that repaired. Make a note on the receipt of what it is and how much for my records. KTHX."
That way, they aren't all upset that you're cheaping out on them and being a big boy working on your own car. Then it's easy for you to get your car and you don't have to go through their b.s. And thus, hopefully, they treat your car well. I imagine angry mechanics losing $350 job that's really easy aren't gonna treat it like a nice new expensive car.
