My 71 Beetle has had a few problems latley, one of which is that it is only running on two cylinders and not four???

The machanic said that he will have to do tests.. does anyone know what the cause could be....

What carby / carbies does it run? If it's a 2 barrel carb one side could have a problem, like blocked jets etc.

Check the points, plugs, leads, dizzy cap and rotor.

Also a compression test would be a good idea.

do you know which two are good, or bad?