what is going on?

i own a 1999 chevy astro cargovan. on my way to work yesterday, it started running very rough like one of the plug wires came off. i pulled it off of the road and shut it off and let it sit for a few minutes. it started right up but the running rough still continues. i drove it straight home (about 5 miles) and parked it. i have checked the plugs in it and they are in great shape (just replaced about 2 months ago) as well as the wires and rotor and cap. i did a compression test on the front two cylinders and they both tested ok as well as a spark test on the plugs. they only thing i can see odd about it all is the spark from the plugs are shooting a sunset colored orange instead of a blue. it has a v6 4.3 i think. i am at a loss. please help me