i have an 04 chevy duramax lly everything is still stock for now. but it looks to me that the egr is already blocked. i can see what looks to be a thin piece of metal sticking out in between the flanges of where the egr blocker is supposed be. Can someone tell me if an egr blocker is able to be seen once installed. i guess i could check for a fingerstick also cause im sure would have a light on if egr was blocked with no fingerstick. i would have posted a pic of the egr. but it exceeds this forums mb. anybody know a way to post pics thx.