A recent scan indicated a malfunctioning EGR (Pintol Position). Is the Linear EGR valve rebuildable? If not, are there any other things I should check before buying a new one.
What kind of adverse effects will this have on engine performance?

Bad effects like KR, high temps, etc. You can try removing it and cleaning it. It works on the Linear sometimes, but is more successful on the Pre-94 digital valve.

I've had very good luck on the 94+ EGRs, by simply taking them off, spraying carb cleaner up in and using something like a small screwdriver to move the pintle valve in and out until it moves freely.

Worked on my 95 and Cfoote'* 96.

Well it cant hurt to try, if its already faulty. Thanks