Put another computer on it, from another identical van. Cranks and runs great until it reaches operating temp. Then it will not idle. Goes dead.k

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your Voyager. Swapping a computer from another identical vehicle might work temporarily, but differences in programming or immobilizer settings could cause issues. The symptoms you're describing suggest the idle air control valve or throttle body could need cleaning or replacement. Warm engines rely on precise air-fuel mixtures, and a faulty idle air control system might struggle to maintain idle. A vacuum leak, malfunctioning coolant temperature sensor, or improperly programmed computer could cause similar issues. Since the problem started after changing the computer, you might also need to verify the compatibility of the replacement and check for proper synchronization with your van's systems. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!