I don't understand what the EGR (Exhaust Guage Regulator ) is suppose to do - what it's importance?

It regulates exhaust flow back into the intake manifold to sapposedly lower emmissions, but it really just cruds up the intake manifold with soot and oil. You can block off the lower intake and stop the exhaust flow, put an F engine prom and it's not there anymore.

dieselchick, i dont think that the egr is of importance, i think it is an emission thing more than anything. pretty sure that a lot of members have dropped them off thier trucks. i dont think it increases performance. do you have an s or f motor? i have an f and no egr on mine. s motors have egr's. i live in pa. also and as you know there is no emission testing on diesels here, so everything is pretty much fair game as far as i'm concerned. if you are looking for performance, chip your truck and get a big exhaust system. lose the cat and muffler also. let your motor breathe and all will be good, and you will be happy.