Firing order for a 1999 chevy s10 pickup

I apologize for the late response...Due to the bad economic situation this site has had a substantial (+50%) increase in the number of questions being asked in the last four months.
I assume you have a 4.3L and not the 2.2L?

For the 4.3L:
Firing Order:
1-6-5-4-3-2

Cylinders:
6-----------5
4-----------3
2-----------1
(front of vehicle)

Distributor:
coil wire-->
-----6------->............<--------5-------
-----4------->............<--------1-------
-----2------->............<--------3-------
............(front of vehicle)

Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!