Alright, I thought I'd try you guys before I lose my mind and drive the damn thing off a cliff.

I've got a 91 S10 blazer, 4.3L TBI, i believe, and I just started noticing this problem the last few days we've had that are cold. Up in Canada, it's been about -20C (21F) to -10C (26F) and after start-up, I'll be driving, I'll give it a bit of gas to accelerate onto, say, a freeway, and it seems almost like a misfire (no CEL) and all my power kicks out momentarily, yet the engine still runs. i'll lose lights, radio, everything but the engine. Since I've had it I've done plugs, wires, cap, rotor, alternator, battery, t-stat, most of the suspension, brakes. But i've just started noticing the electrical kick out in the last few days. It has been doing what seems like a mis-fire for about a month now. We've had lots of warm, then cold weather, changing daily. Any idea's anyone?

 

Do you have a volt meter to actually see what is happening to the voltage?

This sounds like something is affecting the ignition system. The older trucks do not have the complications of the newer ones, but if there is wiring damage under the dash, it could cause a drop in power to the vehicle.