I'd say they ARE NOT going bad at the same time - because it is very likely many of these parts are not BAD at all.

As the Zoo-guy said, get the codes read and come back here - don't just take the car to the crooks. (I mean, it's one thing to throw parts at the car because you don't know what you are doing - it is quite another to rip a customer off in the process by charging outrageous prices for mundane parts).

See why I go off on dealers so much? Also, notice that the manufacturers don't do/say anything about such dealers. THAT bothers me as well - I mean, would you ever BUY any car from that dealer now?