Mercedes Benz repair: 1990 Mercedes 300 SEL, power steering fluid, timely answer

Question
My vehicle has 175K-mi. It just began sputtering and backfiring and would stall when coming to a stop or deacceleration. It would VERY slowly pick up speed and at high speed, run VERY well or normal, without problems. I did notice, smoke coming from underneath the car and hood toward the back. That may be a transmission or power steering fluid line with a leak, I think. The low oil light came on, but oil level on inspection was fine. What occurs if I overfilled the oil? When I'm able to crank the car, it runs very roughly and sputters. Could I have bad fuel or bad fuel filter?
Thanks for getting back with me with a timely answer.
Dr.Larry Goings
601-317-8000  

Answer
The issue could be:
#1. Worn timing chain, guides, tensioner.
#2. Worn valve guides dumping oil into cylinders = fouled plugs.
There are other possible causes, but the smoke makes me consider overheated catalytic converter as very possible.

The oil level sensor could be damaged wires or bad sensor.

Urgent:
I would suggest inspection of Oil Pump Chain and Oil Pump Chain Rail, at this time.
If the Oil Pump Chain fails = new engine$$$