cant figure out whats wrong with my car. on 2002 Dodge Neon

Car loses power when the weather gets warm. does fine in the morning on the way to work, but in the evening, it dont want to climb upgrades and have to pull over to let it rest. have to do it several times. We re-gapped plugs thinking this was the problem. Ive put 3 different coil packs on thinking maybe I got a bad coil pack. Machine at auto zone and advance keeps reading bad coil pack. We thought it was alternater also cuz when u take off 1 battery terminal, car dies. now we're trying a new battery. We just cant figure it out. Car ran fine all winter long.

Asked by for the 2002 Dodge Neon
Tell us exactly what the code numbers are. Example - PO300