My 91 vw cold starting problem

I have a 91 vw passat that has a problem with a cold start. It starts up fine, however, the idle goes down, it stalls out, or will let me feed it more gas. A VW dealer thought it was the throttle switch, that was $500, but didn’t fix the problem. Then, they told me they don’t have the equipment of diagnosing the older cars and told me to go to someone that repairs mechanical problems. The car is in great shape otherwise with 92,000 miles on it. How can I get it diagnosed properly?

This could be as simple as a faulty coolant temperature sensor. Any decent mechanic should be able to diagnose and repair this. I can’t see any reason whatsoever to take a 16 year old car to a dealer.

The fact that the VW dealer told you to take your VW somewhere else should tell you something when it’s time to buy another car.