1998 Chevy S-10 Missing/not running right

My pickup has a weird problem. When it starts up it idles just fine but when any amount of throttle is applied it will bog down, miss, and kind of act like its choking to death. It does this for a few seconds and then the rpm's come back up. Also while im driving around at a constant speed with a small amount of throttle applied it does the same thing and misses and shakes the truck very violently. The weird part of this problem is it seems to get alot worse on days when it is raining or has rained recently. On nice days when it is hot and dry out the truck still has a barely noticeable miss. Hopefully someone can help me out with this, thanks.