1999 C230 Kompressor - hesitation under load

[Tassie]

After looking at 190E's (none in good shape) and C220's (all with major hidden issues) and Volvo 740/940's (all worn out) I took the plunge and bought a 1999 C230 Kompressor. Originally for my daughter but now for my wife, and me, too.

Thanks to all those who have submitted to this site on their W202's. It was very helpful.

It was a one owner car, have a mitt full of service records from new, spare tires and wheels so we are well outfitted. Obviously well maintained with minimal concern for cost. The odometer is 130,000 km or about 80,000 miles.

Took the car home (500 km, 300 miles) and no problems except one odd thing.

On a long extended climb (8% grade) the car ran well but when I floored the accelerator to pass some trucks the car seemed to stall or hesitate, then finally caught and took off. Very impressed with the power but was concerned with the hesitation. At the top of the hill, I pulled over and checked everything out. The car idled beautifully but there was a slight odour of rotten eggs which I assume was unburned fuel trying to come through the catalytic converter. The rest of the trip was without any issue and even in other similar circumstances although there was not nearly the same load on the engine. No "check engine light" lit up.

It has a recent MAF sensor (10,000 km, 6000 miles) along with servicing at the same time. According to the previous owner, this is a city car with little freeway miles.

The car's behaviour reminded me when a previous vehicle I used had its catalytic converter plugged up. Do I have the same issue? I would think that a plugged cat would light up the CEL. Could other potential problem be fuel delivery (pump, filter, other?) developing?

By the way, fuel consumption was 7.5 l/100km (13.5 km/l or about 38 mpg) at 90-110 km/hr (55-70 mph).

Thanks,
Paul