1999 Dodge Dakota Burning oil

I bought a Dodge Dakota last summer and drove it down to school Approx 2500 kms total trip. The truck is running fine and still has lots of power, but is slowly burning oil. It is also having problem with the idle. When idling it bounces between 500-700 rpm. I have not done a pressure test, but have cleaned the whole fuel system and done a complete oil flush. After both processes it has definitely gotten a bit better, but it still not fixed. The engine also has a slight tick during lower rpm's when accelerating, but it seems to go away after you reach 1800-2000 rpm (but it could also be hard to hear because of the exhaust.) The only things that have been changed on the truck is headers, exhaust and a cold air intake. Any suggestions?