A.i.r.?

I just picked up a 1994 Chevy ext cab 1500 with the 350(retired firetruck!)...when I go out looking for engine upgrades a couple of the sites ask if it has A.I.R.

what is it and how do I know if I have it?

I believe it's air injection, ie smog pump...if the truck wasn't build for california u prolly don't have it

You have it . Its a air injection pump used to heat up the cat converter to operational temp as soon as possible. It looks like a cross between and alternater and ac pump. Gm had lots of problems with them locking up. If it was used as a fire truck it might not have 1 that is if it was built for the fire service and not a normal truck the converted to fire service use. Go and look at the cat converter does it have a tube coming out of it and pointing towards the engine area? If it does then it has or had 1