I just fix a check engine light problem, which was an oxygen sensor. Then, a few months down the road, my light comes on again, this time it's a different oxygen sensor! Again, had to order from the dealer, but I installed myself.

Check engine light on, I checked the code and found it to be an oxygen sensor. Simple enough, except for one problem: this car has FOUR oxygen sensors!! Had to find out from the dealer which one it was, and it was a dealer-only item at the time.