Stalling 1994 "W" code

I have not yet done any diagnostics, but have a foot of snow on the ground and no garage to work in. This is a "new" car to me and all problems were existing when I picked it up. Im just looking for "first check" ideas from some who may have had the same problem before I spend hours troubleshooing in the snow and cold. That being said,

1994 4x4 Blazer Tahoe LT. 4.3 "W" code. Known issues, Pass. side knock sensor is unplugged and will not fit to plug back in. No "Temp Gauge" on dash but it lights up when key is first turned on. Now, onto the problem. It can be 10 degrees out and it will start fine. It can be 50 out and it will start fine. When it gets partially warmed up it will stall out, just like you turned off the key. If you hold throttle at about 1000 rpms, according to factory tach, It will run and not stall. Once it has been fully warmed up it will run fine, with an occasional stall. Once it stalls it will start hard, unless you let it sit for a while. it seems almost as if the crank sensor may be going, but I have no experiance with the "W" codes at all, so I am asking for any ideas. No check engine light. If you think it may be the crank sensor, can you please tell me where it is on this engine? If you think it may have something to do with the temp guage please let me know. If you think I am totally off base, please, send me in the right direction? I bought this one for a winter beater for my GF and she is scared to drive it as it is, so she is using my full size for now. Any ideas are greatly appriciated.

Go to a chain type auto parts store that gives free scans and write down the codes so we can talk about them.

I only wish it were that easy. The chain type stores around here will only do obdII 1996+. Thats really not a problem since I have access to a snap-on 2500. It returns no codes, so I am working with no MIL and no codes, thats why I am asking for any type of assistance. If someone may have had a similar problem. If it were warmer then 10 degrees out and a foot of snow on the ground I would be able to better troubleshoot, but as I said in the first post, its just to darn cold. Thank you for responding.