Geez! Wish I could help, but my mechanical inclinations are less than yours.
I hope the tune-up will do the trick.
I have to take my '95 Camry for inspection this month and hope they find nothing wrong with it. It's got low mileage and is in very good conditions as i don't drive it much. But last year it failed the exhaust diagnostic and cost me 280 bucks. Last month spend $640 on brakes. About time to consider trading it in. :)
YOIKS!
I paid $500 for my truck, and If I have an expense like you have had, I'll just go get me another truck! LOL!
I'm supposed to be leaving for Vegas on Wednesday, but I don't know if I'm going to make it. I don't dare do any errands until I find out what the problem is.