I got the car back this weekend. The mechanic had the car for 4 full days and only put 3.5 hours into it. Very frustrating... they need to learn how to use a schedule. They ran some tests as I discussed earlier... Changed the plugs and adjusted emissions... the exhaust smells less rich, and the car is running very smoothly. I'm pretty sure the problem will come back though. It always does this after the plugs are changed... runs smoothly, then goes back to its old ways within like 100 miles.

Maybe I should just keep changing the plugs instead of taking it to the mechanic!!