I recently acquired my 89 300SEL...it seemed to run okay for the first couple of days...except for a slight hesitation when starting from a stop.

Then today, I had to sit through almost two hours of stop-and-go socal traffic... and it seems like the car didn't like it too much. The CEL came on, and the car started acting really strange. When coming to a stop, it would act like it was going to stall, it would hesitate when trying to accelerate, if I didn't ease into the throttle slowly, and the idle will surge slightly on it's own once in a while. (I had to mash the brake pedal several times to keep from running into the person in front O_O) Also, there is a lot of smoke coming from the exhaust under WOT. I got home and checked the codes, and it is throwing a "code #4", which has to do with the Air Mass Meter, correct?

I should also add that the car is almost impossible to start when cold...I had to crank for nearly 10 minutes off and on this morning to get the engine running. The whole time I was cranking, there were light wisps of smoke coming from the exhaust...the smoke also smelled strange, not like coolant or oil, but more of a caustic smell...like nail polish almost.

Anyone have any insight on this? It's really bothering me, and I can't seem to find much info about the W126 chassis on the net...

Thanks!