We just recently bought a used 2000 Ford Contour and the car runs fine on city roads but when you get it out on the highway it struggles.

We called the guy who sold us the car and he seems to think that it's a speed control sensor/switch? Something we can replace ourselves?

Does anyone know where we can possible begin to find such a thing on the car?

On the highway, once you reach a certain speed..60 MPG it struggles to maintain speed...it's almost like it's not getting enough fuel the way it jerks around, but we had the filter and fuel system flush done..

 

Jen, your description is too vague for me to pin point a source of the trouble. I suggest you take it to an independent mechanic and have him diagnose the problem.