Throttle position sensor?

I have a 2001 Chrysler Voyager. It has 60,000 miles. It has a 3.3 engine. Every year when it gets hot outside the check engine light comes on and the van shakes a little after ignition. The code that comes up is for a high voltage throttle position sensor. We have taken it to the dealer and they change the senosr but it still does this in hot weather. The air conditioner seems to aggervate it. It will shake but later run ok. We have even had the entire throttle checked out and nothing can be found. The last sensor that was changed look damaged. Others have appeared fine that we have had changed. Someone told my husband that it was probably the computer. We are driving to Laredo and then on into Mexico and we want to get this taken care of. Thank you for your time.