2007 Caravan MAP Sensor issue- code P0068

Hi Folks, first time poster.. I own a 2007 dodge caravan, in the year I've owned it I've had a MAP/Throttle position sensor replaced.. the problem I was having was basically the shifting out of first gear would be very inconsistent.. it would rev up very high RPM's then shift, or we just let off the gas to induce shifting.. sometimes it would shift hard..  I took it to the local repair shop, they replaced the MAP sensor.. 6 months later the problem resurfaced.. the local repair shop replaced the sensor again, 6 months later, it's happening again.. they explained that the check engine needs to be on for them to determine the issue.  Well the check engine did come on.. they said the check engine light went off, and this time they're insisting that the sensor is probably fine, and that if the check engine light goes off again I need to take the vehicle to the dealership for them to re-flash the computer on the van so that the sensor and the computer communicate and the issue would go away.  I drove the vehicle home and the problem is still there, while intermittent .. I went thru 4 stop signs, and it rev'd high for 1, and shifted normal for the rest.  I guess I'm asking if it would be advisable for me to take the van in to a dealership and ask them to re-flash the computer so the sensor issue would 'fix' .. I am going on a trip in a few weeks and I don't want this shifting trouble to re-occur while I'm 500 miles from home.. any suggestions or advice would be greatly appreciated.