Hey everyone, I've been having this problem with my 99 Chevy Blazer.  About a year and a half ago while wheelin with some buddies I ran it through a puddle and took water up the air intake.  Needless to say after killing 2 batteries and 4 days of work in the cold of christmas i finally got it running again after getting all the water out of the pistons.  Ever since then it tends to stall whenever i idle, apply very little gas right after idling, reversing, or if I'm stopped or applying no gas on an incline.  ITs a very random thing.  Somedays it will be fine and it wont stall at all but other days its like no matter what i do it just keeps stalling.  At startup i have to hit the gas a little to get it to stay running, something i shouldnt have to do with it being fuel injected.  Anyone else have a simular problem or know of a solution.  I tried one of those fuel injector cleaners as someone said that they may be full of whatever gunk got into my engine when i went throught the water but that didnt work.  All advice is greatly appreciated  

Pull you distributor cap and check the cap and rotor for any build-up on the contacts. If you get moisture under the cap once, it tends to stay and corrode the contacts. Don't try and clean the contacts as teh gap is important, just get a replacement.

 Pull your plugs wires, check them for corrosion by bending them, if the make any sort of noise being bent or are hard to bend, replace em. Dont forget to do your cap to coil wire. My buddy's 94 S-10 4.3L was barely running, cap to coil wire was corroded inside and the coil was grounding to the block every so often, instead of going to the distributor.

Test your coil and check your computer for crappy terminals.

Good Luck.