when i turn the steering wheel in my truck,about 45degrees in either direction, while its parked and idling the rmp drops, to below 400rpm.
do i need to wrry about this? i know the day before a noticed it it didnt do this.
My truck idles at around 1000rmp or just a hair above,

 

normal operation.
power steering pump is compensating, which is putting a load on the engine and therefore it idles higher to react to the load.