96 4.3 V6 Rough Idle

I got a 96 S10 with the Vortec with the central multipoint fuel injection ever since i got it has had a rough idle. i have put a new Fuel Filter on and ran injector cleaner through it. i plan to change spark plugs, wires, and distributor cap soon will this fix it? if not could you please tell me what would.
Thanks!

I doubt if that will fix it, but it's the best place to start. Make sure you don't use junk aftermarket parts. Check this Thread (http://www.automotiveforums.com/vbulletin/showthread.php?t=768557) out on what brand parts to get. Check the air cleaner and PCV valve also.

Is the SES light coming on? If not, does is come on with the key on and the engine off?

What's the 8th letter in the VIN, a W or X? How many miles on it?

The air cleaner is good and i will replace the pvc valve. the SES light is not on but with the engine off and key in the on position it does light up. The 8th letter is X and it has 125,000 miles on it

When you pick up your tune up parts get a new gasket for the EGR and check out the following after doing the tune up. With the tune up and the below it should take care of the rough idle. The below should be done when a tune up is done.

Exhaust Gas Recirculation (EGR) valve - Simply remove - clean with brake cleaner, carb cleaner, etc. - reinstall with new gasket.

Idle Air Control (IAC) valve - Remove - clean pintle and port with brake cleaner, carb cleaner, etc. - reinstall

Mass Air Flow (MAF) sensor - Gently clean with brake cleaner or electronics cleaner - don't use carb cleaner or similar products because they will leave a residue that will have a negative effect on performance.