When I apply vacuum to either nipple it doesn't hold. I want it fixed because I assume the car is stumbling at low rpm, usually while trying to accelerate away from a stop sign slowly, because of this. It Is not holding vacuum normal for this type of vacuum advance? I thought the same about the uniformity of the pin hole but figured I'd ask since a hole in a device intended to hold vacuum seemed strange to me. I don't have any experience with these devices. I figured replacing it would be a good way to rule it in or out as a source of the problem