First, make sure you don't have a blown plenum gasket. Look down the throttle body and see if there's oil in there. If there is, the gasket that is in between the plenum plate and the intake manifold is blown and the intake is sucking oil through. This kit will fix it and prevent future problems as well: http://www.hughesengines.com/Index/p...3&partid=26190
If you do the plenum fix, you might as well do the Kegger mod found here: http://www.ramforumz.com/showthread.php?t=80192
You will have that whole thing opened up anyway, so you might as well clear out some restriction and let the air in better.
Instead of doing the first two mods, and if you want to spend some more money on the intake, you can get this: http://www.hughesengines.com/Index/p...=&partid=24773
This will completely eliminate the plenum problem by replacing the entire intake manifold. You should get some better throttle response and power with this manifold.
Installation guide here: http://www.snowdigger.com/the_garage...es_intake.html
This throttle body mod is free, so give it a shot and maybe add a CAI too: http://www.ramforumz.com/showthread.php?t=46431
For some more serious mods, a set of 1.7:1 Harland Sharp roller rockers is great for adding power. It increases the valve lift. You can find some here: http://www.summitracing.com/parts/CSP-S70037/
And a good installation guide here: http://www.pavementsucks.com/tech-article-32.html
And another one here: http://www.snowdigger.com/the_garage...r_rockers.html
A good set of headers for not too much money: http://www.summitracing.com/parts/SUM-G9045/
Get an SCT Tuner from Hemifever too. It's the best one I am aware of for our 1996 trucks. Get it last because you will need to tell Hemifever which mods you have done. Better to have everything done first rather than have to change a tune later. http://www.hemifevertuning.com/SearchResults.asp?Cat=25