2000 BLAZER w/emission problems
 

I took my blazer (2000) to the shop today, and they told me that i need to replace the air pump assembly. i plan on purchasing the assembly at a lower cost on line.

My question is: does this sound right to anyone? i was told that this air pump is a "GM" thing, and its a pain in the butt, because it ties directly into the emissions.

Please help