throttle body trouble

I have a 2001 desert runner xe 3.3L. I just recently tried to put a throttle body spacer by Airraid on it and while I was trying to get the throttle body off I pulled what looks like a sensor of some sort off the left side of the throttle body. It's some plastic thing held by two screws and it has a metal piece on the inside conected to some spirings. There are two plugs that plug into it. Well when I put it back on I dont think I put it back on right because now when I start my truck it almost dies right after start up and then go up to about 600 rpm. then when I put my truck into gear the rpms automatically go up to about 1300 rpm. also when I start going 1st gear has good power and then 2nd has almost nothing. when my truck goes to shift the rpms kick up high by itself and hesitates to shift. What is this sensor and is there a certain way to put it back on?