my jimmy runs like crap need help!

i just recently bought i a gmc jimmy st 2wd 4.3l automatic and ive been having some issues with it stalling. it is to the point now if i let it idle it will just stall out so i have to keep my foot on the gas to keep it running. also it has points to were it starts to miss like crazy while im driving a day or two ago it wasnt as bad with the misfire but now i dont even wanna drive it. yesterday i took my egr off and cleaned it and put it back on and the rest of last night it only stalled one time but it would idle fine the rest if somone could just give me some advice that would be a big help.

thanks, justin

p.s. i also have anouther 4x4 jimmy that runs great it was just in an accident so i cant drive it i could rip any part off i need.

Check for trouble codes...here's how...thanks Blazee!

http://www.automotiveforums.com/vbulletin/showthread.php?t=553044