This beast is not pulling any codes but has progressively become harder to start. I understand the cold weather issue may be a factor but I think there is more to it. When we try to crank the truck it will turn over and sometimes it will try to start but it seems like it is not getting enough gas. It will start sluggishly when we put starter fluid in via air intake but it runs really rough like it is starving for air/gas. We checked out the fuel presurre which is good and checked the fuel pump also good. So we changed the spider injector and it ran well one test drive then returned to its normal issue the next. Once you get the truck started for at least 20 to 30 minutes you have a rough running truck. Acceleration
is hard because it feels like it is gasping or some one is just tapping the pedel. Once it had run for a while the truck would start just fine for the rest of the day only to return to its' wicked ways in the morning. Now of course it is getting worse and if left to sit for longer the 4 hours it has the same old problem...however there is snow and ice out now. We did do a tune up and it worked perfectly for a few days then one morning it was back to its' old self. The new plugs and wires still look fine though and as a side note most everything on this thing has not been changed since it came of the line from the looks of it. We think we might have a clogged cat and can remove with out issue because we don't have emission in the county we just moved to but I want to make sure this seems logical first.

 

Had a chick I dated a while back that owned a '96 Blazer, wasn't 4x4 though. Any how, the trucked showed basically the same symptoms your seeing now, turned out to be bad O2 sensors. They thought the engine was getting too much air and it actually wasn't getting enough. Can't remember exactly which one's, but I'm sure the process of elimination will help out there.

 

Donjuan,
Checked the 02 sensors and they are fine, have a lead on another option that I will post once it is tried.