Why does my citi golf start up but does not rev?

check the timing. if it is running to rich, every time you give it gas you are going to flood the engine. if that is not he problem check the mass airflow sensor. it should be right after the intake filter box and before the intake manifold. if the sensor is stuck closed it will tell the computer to add more gas making it run rich and you will have the same problem. if that is not it check the O2 sensor. it should be right after the catylitic converter on your exhaust pipe. with this its the same thing. it could be stuck closed...... in a more extreme case, one or all of your intake valves might not be seating correctly. i would then take it to a shop that specializes in working on volkswagons.