Thank you all very much. Bookmarked that OBDII diagnostics.

I learned a ton of lessons on this, and not all great unfortunately. The $4000 debacle was do to transmission fluid that had leaked through the car and into wiring it seems - as they showed me fluid everywhere. A bunch of very expensive parts ordered from the dealer later, and I still had issues.

I was pulling together all my previous invoices to find a new mechanic, and i noticed a comment in the notes section of an invoice from late 2014 that said "engine or transmission leak, should be monitored".

Now granted, it's my responsibility to have read my invoice completely but I'm still angry. I never, ever, ever let things like "leaks" go - if they had mentioned it to me we would have had a plan to fix it asap. Most likely could have prevented this expense..

But at least now everything is fixed again and I can drive without getting stranded and towed home :-)