Okay, I'm technically challenged so I need some help here...I have a 1989 FJ62 with almost 88k miles on it...and it idles rough. The dealership said it needed an EGR valve replaced....I called NAPA to order a part and they said their books don't show a EGR valve, only the gaskets....DUMB QUESTION TO FOLLOW: is it advisable to just try to replace the gasket to see if that is the source of the gasket leak....or should I take it back to the dealer (2 hour drive) for them to service?