it idles at around 1000 when just started, and idles at 500 with a little jerk( to 600) after i drive it for a while. Is that normal or too low? Any suggestions?

WHat is dirty and what should be replaced? Because I am goning to the dealer this week to fix my "check engine" light problem( maybe O2 sensor), and I want to get all the problems away in one trip.

 

Your Check engine light is probably what's causing it to idle so low. Your ECU is running is safe mode right now until the problem is fixed.

 

you might need to get a tune up