Hi! I just purchased a 1986 560SEC from a friend of mine and need a little bit of help diagnosing somethings with the car.

First off, could someone link me too a good source of reading pertaining the fuel system on the car? I would like to familiarize myself with the fuel injection and emission system of the car!

And which leads into my current problem. I'll give you a little background info. I bought the car in LA, and drove it back to the bay area, which was a bit more than 300 miles. It got great economy getting back, easily over 200 miles to the tank(the speedometer does not read so I couldn't calculate the mileage heh). But when I did return home that night, during some street driving, i noticed the 02 sensor light on the dash became illuminated.

Throughout the next couple days driving the car, the fuel economy has been way less than stellar(and I definitely don't think its due to the huge V8 under the hood) and the light keeps coming back after 5 minutes or so on the road, and sometimes will turn off, and re-appear in the same trip. I have driven less than 160 miles and from a full tank on saturday, to today I have around a quarter tank. I don't think that is normal, and I did not hoon it around either, drove it like a grandma. So I believe the possible super rich condition and this 02 sensor light are hand in hand. The car did have its 02 sensor replaced and tuned according to my knowledge previous to my purchase.

Anyone have any insight? Thanks!
-Kyle