I have read some threads about erg blockers but none explain why or what you might achieve by doing so.
any ideas

It's to keep all of the impurities out of your engine. It prevents dirty Ehxaust Gas from Recirculating back through the intake system. You will need a tuner or a "fingers" stick to bypass the code it will set by doing so though.

Here: http://www.dieselplace.com/forum/showthread.php?t=257214

Read this.
http://www.dieselplace.com/forum/showthread.php?t=24719

i blocked mine yesterday and i still havent seen a code yet. does this mean im not doing to get one? and its not fingered

and if one does show up or if it doesnt i guess, either way, do i need the finger stick? if it does come on and i dont mind having the light, will it do anything else or just have the light on all the time

I have read some threads about erg blockers but none explain why or what you might achieve by doing so.
any ideas
You need to learn how to use the search button.
http://www.dieselplace.com/forum/showthread.php?t=257214

my plates been on for 2 months now and no codes