Just bought a 2004 Dodge Rumble Bee that I am going to restore. It has a 5.7 Hemi. Truck will not idle, runs sounds good when you sit on and keep foot on gas. but there is no check engine light on. The truck sat for almost 8 months and the battery was dead. I have replace the MAP sensor and the sensor in air box, still nothing. I have been told that with these new systems if the battery goes dead it takes the computer system some time to recalibrates itself. If so how long does it take or how many miles do you have to drive it. Any truth to this or any suggestions. Truck won't be ready for some time to put on road.

Lots of truth with that, but I would be looking at a lot of other things as well- comp tests, fresh fluids, plugs/boots, but very, very important-fresh fuel......

clean the throttle body

Does it have the Mercedes sensor under the battery box?
I've pulled several of these, some have wiring issues.

I've hd throttle body out. It is clean and appears to be not that old. Yes it does have some sort of round sensor under the battery. Was told it was for heat in battery if battery gets to hot. Would that effect the the motor not wanting to idle? If so, what is best way to fix. Is there a sensor for this.thanks,