Been having issues with my '90 300sl 5 speed. 5th gear doesnt work, all other gears work great. Cruise control doesnt work. Ive seen that a bad airflow potentiometer can effect cruise control, and the airflow sensor is also an influencing parameter for the 5th gear change according to the WIS documents on the computers at the mercedes dealer i work at. What do you guys know about this? Sometimes off idle i get a hesitation for a couple seconds and runs great after its off, and sometimes i have no problem at all.