Sorry to post this again. My 1987 190e 2.3-16v has been having trouble lately. For about a week now the oxygen sensor has been coming on. It comes on every once and a while. Lately, it flashes on and the engine chokes/stutters simultaneously. It's fine sometimes...5 min drives and such...but after driving for 20-30 min it starts to choke every now and then. Sometimes it will stall completely unexpectedly. This leads me to believe that my previous thought (The Cat Convertor being blocked up) is not true. In one case, the engine was cold and it began to choke and stall incessantly with 02 sensor light on within 5 min of driving the car. My thoughts are...Loose connection on the 02 sensor, causing imbalanced fuel/air mixture...Possible blockage of the cat convertor (though it passed smog only 2 weeks ago)...Need new 02 sensor completely...Major Damage to fuel system (injectors, pump...) Please help, the car is inoperable. Thanks for your time.