92 GM Oxy Sensor

My Check Engine Light comes on, goes off, comes on. Happens when I am on the hiway after about 5 minutes. Assuming this is a sensor problem, no performance problems noted), I am willing to replace the oxygen sensor. Anyone know where it is and what it looks like? Any other ideas--clogged EGR port?

ok from my experence with my 92 gm LS the codes i get are 172 and 173 which is for fuel control meaning that its running lean not been able to find a cure for that yet but ur problem im guesssing if uve never done it before is the egr ports wich if u take your throttle body and elbow off ther the horse shoe looking things on the manifold ull see them right away what i did was used a small screw driver and sum carb and choke cleaner and i cleaned mine up pretty good so hope this helps have u had it scanned at like auto zone?