Rep Power: 0

after driving for a while when i come to a stop and have the car in neutral it starts to idle up to about 2000 rpms and then drops to about 500 rpms. sounds like its going to stall when it drops and lights dim drastically. any ideas?

 
Rep Power: 189

Check the battery terminals make sure they are all tight, clean and secure, also check and clean the engine ground straps and then in the engine bay check the fuse panel it has 2 philips head screws make sure they are tight. Next remove your intake tube and then clean the throttlebody with throttlebody cleaner, also check the condition of the air filter and all vac line while you are at it. High idle can be caused by a few things but eliminate the simple stuff first off.