1997 Volkswagen Jetta Q&A
1997 Volkswagen Jetta Question: speedometer works intermittently
get under the dash run your arm up to the back of the speedometer till you feel something that feels like a box the box could be loose or wires going to the box could be loose. I just solved the very same problem today. - HeatherGilliland
I have the same problem with mine, spoke to a family friend who's a mechanic. The volkswagen speedo is controled by a series of plastic spokes. Over time they get worn down and the teeth may not be touching anymore. I've noticed with mine it works more in the winter (when the pieces of plastic are very cold, and not as soft as a hot summer day) however if they work when I start the car, the will not work if I turn it off then back on. The only thing you can really do is get a used gauge cluster, bad part is the mileage is electronically controled, and only vw dealers have the ability to change it to match your vehicles. - Visitor
A dirty or failed throttle body can cause various drivability issues and illumination of the Check Engine Light.