Originally Posted by Jay W

I have a 928 with CIS and it sat too long and the fuel distributor gummed up inside. It would idle fine but as I gave it gas it would start to stumble. It turned out that the plunger inside the center of the fuel distributor which hovers inside rather than be connected was hanging up on sticky gas and not allowing the fuel mixture to adjust in sync with the air plate. After alot of diagnosing, all it took was spraying a can of carb cleaner through the top and out the bottom of the fuel distributor and it ran perfect.