I serviced my B5 2000 1.8lt about two weeks ago. It has done 190 000km. It was missing when i was driving. The mechanic said it was the air, fuel sensor unit that was faulty. So he replaced all my filters, spark plugs oil and that unit. So r4000.00 later I have a problem. In the morning when the car is cold and I start it... It starts and then not even 5 sec it dies. So then I unplug that sensor, and then it starts. I can drive like that but then the car idles uneven and dies like at the trafic light. When the car is warm during the day I plug that unit back in and then it is fine. But the next morning the same thing. Can someone please help?

 

Sounds like it could be a bad coolant temp sensor. They are pretty inexpensive and easy to replace.

Jason

 

I will try replacing it then first. It is just weird that if you unplug the mass air flow unit (brand new) it starts normally. Thanks. I'll let you know if it solved the problem.