Expert: Sean Halliday - 1/11/2007

Question
i have a 1991 volkswagen golf 4cyl 1.8. when it is really cold out the car will rev high when it starts. when you get it warm and drive it will buck spraticly but when its warm out it drives fine. does not feel like the tranny. do you have any ideas that might solve this problem. thanks a lot.   joe  

Answer
It may be your MAF sensor.Thats the mass air flow sensor and goes between the air filter and throttle body.All mass sensors are heated and when the sensor isnt working,the intake air isnt the correct temp so the car will do strange things.I would have it checked according to the manual as there are different tests for this.I would also look for a leak at the intake manifold using a vacuum tester,and any leaking hoses.One other thing about the VW golf,the crank breather system is crucial on engine performance so this breather sytem must be in good shape and if it gets blocked with any carbon or oil then the engine runs poorly so make sure its ok.I see its a 1991,so im assuming its got a few miles on the engine.Time for a thorough maintenance check.Basic things as well such as the air and fuel filter change will help.Plugs,cap,rotor,wires.Timing belt and visually look for anything that needs replaced.