Stalling Plymouth Acclaim

This car is stalling after driving down the road for 15miles, will restart immediately and then run for a while and then die and restart. Sometimes it restarts and then dies right away. The engine will spit sputter and die, and sometimes dies right now while going down the road. If you put the car in neutral you can sometimes keep it running. It seems to do this when it is really warm and humid outside. It has coded the code 25. Which has to do with the AIs motor. We replaced it. The code cleared, and then when we drove it, It coded that code again. When it is cooler, ie in the evenings, and you drive it, it will not die. It runs very well until it decides to go through this fit. It did this last summer too, only not as often, and then never had a problem until this high heat and humidity showed up.
The car has spark after ithas died.
The odometer on the car has now quit, but the speedometer works.
Any suggestions for this?
Please advise.