I have always been curious about what an EGR system actually 
 accomplished? Does recirculating a small amount of exhaust gas 
 actually cause the engine to run cleaner? My 78 had this system 
 plugged and the line pinched when I bought it, I have been going one 
 way then the other about replacing it or leaving the closed of 
 components in place. Suggestions anyone.

TIA
Clay