I have a weird one. When the car is stationary, I can rev it and the rpms go back to normal when I take my foot off the pedal. Nothing wrong. But when I put it in gear, it takes off, I take my foot off the accelerator, but it keeps accelerating. Also, when I take off, every now and then just before the clutch fully disengages, the car shakes violently and it pops out of gear

UPDATE Turns out the clutch problem was the bowden tube not adjusted properly. The acceleration problem still remains, but I have noted the peddle doesn't go back to where it started when I take my foot off?

Front gearbox mount possibly?

My first thought, replaced last month

Recheck front mount to see if still tight.

Clutch cable is snagging on accelerator cable?

UPDATE Turns out the clutch problem was the bowden tube not adjusted properly. The acceleration problem still remains, but I have noted the peddle doesn't go back to where it started when I take my foot off?

disconnect at the carb and see if that works correctly

If it does it is either
1) cable linkage problem
2) pedal problem

I am guessing a pedal problem if not carb problem
Often the spring breaks or the bracket / welds brake

When the cable is disconnected make sure the pedal is still "up"