Help diagnosing a problem..

[HillBilly]

My father drives 1992 Mercedes Benz 500SEL with about 180,000km on the clock. Just recently, it started to idle very rough, and has very bad hesitation under 3000rpm. Once the engine is warmed up, it runs perfect. O2 sensor?? What else do you think it could be?

[Mitsu3000gt]

Could be the MAF, but O2 sensor would be my guess.

I'm guessing a couple minutes on a diagnostic machine will tell you all you need.

Mark

[The Cosworth]

O2, cause once it heated it would warm up the sesor, it has to be self heated before that... so my guess is the heater coil is gone...
so a new one would be in order

when is the last time it was changed?? they are supposed to be done every 60 - 100K

[HillBilly]

don't know if it was ever changed. Are there pre-cat sensors on this car? How many 02 sensors total?