^It's hard to find 1g's with that black cap on the TB now-a-days, I've only seen one in person that still had it. Best thing to do if the cap is not there it pour some silicone and let it set so then the screw can't back itself out.

Usually the cause of idle surge is the ISC (Idle Speed Controller) but there's other various components that can cause it as well.

Go to VFAQ Site - Visual Frequently Answered Questions and their should be a idle surge faq there... I think there's also one on Talon, Laser, Eclipse 1G Info DSM. You'll find most your answers there.