so today u noticed that my driverside headlight was out. so i changed both headlights out and after putting my battery back in (since i had to remove it to get the driver side light out) i noticed that my idle rpm had dropped from about 1,000 rpm at idle, to around 500-600 rpm at idle. my question is, do you think this is bad or is this normal?

 

It sometimes takes a couple dozen miles to get the ecu recalibrated. If it doesnt get back to normal shortly then clean the terminals.

Also, did you change just bulbs or change housings with the bulbs included? If just bulbs, what did you take out and what did you put it?

 

The ecu has an idle relearn procedure. When you disconnect the battery you are supposed to start the car and let it idle for about 15-20 mins before driving for proper calibration.

 

i replaced only the bulbs, factory bulbs replaced by silverstreak(i think)