Spuradic Rpm

I just bought a 95 silverado z71 4x4, the truck runs solid and has no severe issues. When driving in town you speed up and ofc rpm raises, but then when you let off the pedal to come to a stop a a light the rpm drops to the brink of dying then bounces right back to norm. I am at a loss as to where to start but it is driving me insane. Is there anyone out there who has had this issue and can help?

Clean your throttle plate and idle air control motor with throttle plate cleaner.