Checked the potentiometer today and it seems fine. Adjusted main flap and readjusted co2. Car stumbles and has hard start problem now! Backfires and is not going into closed loop. No one in here has been any help. I am aboutto stick some explosives in the tailpipe, light it, and call it a day! Seriously I am going to farm this one to the Benz dealer!!! Let them have the headaches!!! I am tired of this car!!!! At this point I think it needs a computer for the fuel injection!!! Told the owner to buy a american car since they a bit cheaper to repair and have half the electrical problems that german cars have!!