Volkswagen: fuel injectors, rubber pipes, coolant temp

Question
good day i have just aquired a 1988 e reg 1800 16v gti golf i seem to have a problem with the idling the rev counter keeps jumping from 1 to 2
and then cuts out,it starts first time no problem,the previous owner said once it warms up its fine,it jurks when you go slow but as soon as you accelerate it seems fine,can you please help,thank you.  

Answer
you need to check the warm air pipe from the exhaust manifold pickup to the air box, also check all the rubber pipes for leaks or cracks. if both of these are fine then it may be the idle stabiliser valve that is playing up. all three of these are common problems, and can all cause similar faults to what you describe. also the engine coolant temp sensor can cause poor cold running and lumpy tickover. hope this helps.