2001 GMC Jimmy problem

Alright, I have a 2001 GMC Jimmy with 102,000 miles on it. Lately it isn't running well, I am getting it into the shop tomorrow but I was hoping perhaps someone could shed some light on this problem. 6/10 times I start it, it goes to 1700 rpms, then slowly drops, drops, of course insanely rough idle, death. Then sometimes it will start up fine, run at around 1100 rpms until I put it in drive, then it slowly dies like before. I can keep it running by pumping the gas, so I can get it places but it WILL stall like shit on me whenever I have to slow down or stop at a stop sign or stop light.

Anyone have any idea what it might be doing? It seems unlimited, I've read a few sites that say they replaced their idle speed motor but they didn't describe their problem like mine nor did they have the same car.

Have you pulled the codes yet?