Unlikely to be the rotor arm. Have you replaced the air filter - they get clogged but remain looking reasonably clean. Try the car without the air filter and see it the problem remains.
Next .... suspect a fuel supply problem. Clean the fuel filter and check for kinked pipes.
Tip ... with air fiter removed and a clean lint free cloth in your hand, rev the engine and firmly block the air intake. The suction will frequently unblock any jets. Be certain to use a lint free cotton cloth and don't let it be sucked into the inlet!