So my dad recently bought 2003 RAM VAN and the car runs fine when cold drives switches gears normal but when it gets to running temperature 140, it stalls when in gear.
Like when i stop at traffic light it would stall if i dont press gas, in neutral its running but a little rough. There was check engine light but my dad disconected the batery so now the car doesnt show any codes. Any ideas where to start looking ?

 

Check the plugs/wires/cap/rotor for age/condition. Clean the throttle body. (take it off the van, and clean it, pay careful attention to the IAC well. it likes to collect crap. ) How many miles on it? Might be time for O2 sensors as well.