Larry, if a cam lobe was worn, but the valve was still opening, the choke on either induction or exhaust wouldn't necessarily show at the low rpm's that the starter will produce. Once the engine gets going, the choke will be evident as the partially opening and closing valve will now make it's presence known. Just a thought. Maybe remove valve cover, get a dial gauge and measure the lift on each valve..
2000 Dodge Grand Caravan SE