S.E.S on Interstate only?

[Zzade1989x]

Hey guys


I have a problem with my 95 Grand Prix. It has the 3100 V6 engine and 82k miles.. when I go on the interstate at a constant speed of 55 or 60mph the service engine soon light comes on and stays on till i get off the interstate. If I get off the interstate and drive around town doing erands the light will go off as i drive around...or if i just shut it off and turn it back on it goes away..hasnt given me any problems so..What is that??? stuck EGR?

[crashman]

Ya need to have the codes pulled up, that way you'll have an idea where to start. "Autozone" will do it for free.