Hi folks,
I've been having an issue with my '74 240D (automatic) and it's weird idle for quite a long time and need to finally sort it out.
The short version: when it's in park or neutral when cold, the idle is nice and low. When the engine is warm, the idle in park/neutral is ridiculously high. BUT if I put the car in drive, the idle drops to where it should be. I've since been turning off the engine with the brake pedal down and the car still in drive, otherwise I can't turn it off!
I made a video of the issue to demonstrate it better:
https://www.youtube.com/watch?v=GnyLXM9sW9s&t=7s
When the car is cold, there's no problem. But after driving for more than 5-10 minutes, it's an issue.
I have already measured the throttle linkages across the top of the engine to ensure they're the correct length (they are) and adjusted the idle by the screw on the throttle body, so I think the problem is elsewhere.
Any thoughts? Linkage problem or something more vacuum related?
Thanks
