My problem about a year ago, started with as I.

My problem about a year ago, started with as I was driving my minivan it would hesitate (like it wasn't getting the proper flow of gas or maybe I had gotten some bad gas). We had the transmission fluid changed and all related items checked. The service department couldn't find anything other wrong. Still there were times when the vehicle would do the same thing. Finally, as I stopped for a traffic signal, it stalled in the middle of the highway. It was difficult to start, but finally got started, but with a jerking motion. Finally I was able to drive home with. We had it towed to repairman, he informed us it was the transmission, where just recently we had the transmission installed. It was find for a couple of weeks, then it would not start again. This time the mechanic installed both starter. This time no problem, it started, this went on for about a week. Spoke too soon, it started again, it turned this time only it wouldn't idle. Again, tried three times and then it wouldn't turn at all. So what is the problem, should I just get rid of this van. Its in good condition, looks good in and out, has been serviced on a regular basis, oil change and all. Can you figure out the problem or is the solution is to sell, swap or trade? HELP! Note: I would be glad to donate, if the answer will solve my problem, right now we have spent so much too much, and still the problem has not been solved. Please help