I can't seem to get my car to move unless I get the rpms over 3000. We've changed the fuel pump, fuel filter, and the fuel sensor all with no luck. It will start and get to where Im going, but if I come out and try and start it up again, it wont go. Ive got to let it sit for about 45 minutes before it will start. Also having problems overheating after flushing the trans. Any help would be very welcome, before I break down and take it to the shop.

Did you check your plugs/wires?