87 carbed 1.5 looking for the source of erratic idle. Checked all the stuff that was easy, then got out the carb cleaner and started spraying around. Got a rpm increase around the back side of the carb joint. I have read that they fail now and then, but I am not gonna tear it out and replace it based on that. Is it actually common or am I just projecting and the leak is probably something else? If it is the joint, will rtv seal it up?