Check engine light goes on after 20 miles =/- and I am getting 13 mpg in my 1994 eurovan. I can't find anyone who has an OBD1 scanner to dignose which sensor needs to be replaced. Help??

It goes off after stopping and restarting. The light is a steady amber. What repairs are necessary?

it,s a 2.5l, 1994 eurovan.

Where is the thermostat and the Engine Coolant Temparature Sensor in a 1994 VW Eurovan 2.5L 5 cylinder gasoline engine?