Is there any other reason why my trucksags on the rear driver's side besides bad air bag?

 

Sure, but could use some more information, what year, how many miles on the truck, how often does it drop?

 

It is a 99 SE7 w/ 130k. I can be sitting in the vehicle and hear the compressor kick on every 5 minutes or so. Give or take a few. By the way, it turned out to be a bad spark plug on the misfire issue. I am not sure if you remember us talking about it or not.

Wm

 

With your mileage, and not alot of information, I am going to guess you need new bags, Arnott has them on sale for $129 each, make sure to replace both.
As for the plug wires, have you replaced them, if not, consider ordering a set of 8mm Magnacor wires.