911 lurching or bucking under constant throttle. Help?
 

My 1970 911 has a tendency lurch under constant throttle which causes which causes the throttle linkage to pull and lurch more until I push in the clutch.
Transmission and engine mounts appear ok.
I can avoid the problem by slipping the clutch.

Not sure I understand exactly what’s going on, but seems like a clutch or fuel issue. Have you done anything else to the car recently?

this has been going on for a long time

Had the same problem with the car surging and slowing at a high frequency, say every second it would surge/slow under constant throttle until undrivable. Push the clutch in and let it settle for a few seconds then all fine for a few minutes until it started again. Whilst accelerating or decelerating no problem but after a few minutes at constant throttle it would start all over again. Mine is a "85 so I imagine completely different induction setup to a '70 but my very good mechanic identified a dodgy mass flow air sensor. Replaced that and has been all good since.