Car was running fine until new battery was installed,now car stalls when you idile

Check the ECM grounds, they are under the passenger side kick panel. When the engine goes to warm status, the Oxygen sensors come on, If there is no ground on the ECM then it starts pulling ground voltage across the sensors and that causes big issues.

Check the alternator to see if it's working. If the battery is 3 years or older then you should have it tested too.

Engine stall or RPM fluctuates at idle.

This problem is commonly caused by a dirty automatic idle speed control valve and throttle valve. Buy a can of throttle valve cleaner (do not use carburetor spray cleaner!) from NAPA or Carquest (made by CRC chemicals) and spray it into the air intake while the engine is running, use up about 1/2 the can, engine will try to stall hold the speed up, shut it down and let it soak for 30 minutes, restart and blow out the remaining fluid, shut it down and disconnect the negative battery cable for 5 Min's to reset the base idle control

Maybe it's the anti-theft system an not the remote start . Is the SECURITY light lit on the instrument cluster ? GM anti-theft systems will disable the fuel injectors if there is a problem .

What year is your van and what engine do you have?

your having a vacume problem or your egr valve is bad.

For sure the timing is out, these cars are a mess to work on. Bring the car to someone who knows what he is doing. Good luck with that.

Its idiling fast cause ur choke is on it mabey broke and flooding the engine check your choke valve

ok this sounds easy when you ran the vehicle the computer controled the idiling motor now that you replace the idiling motor the computer hasnt been reset to except the new parameters
once you reset computer this should bring the idle back down to its specified idle
you can also adjust back of gas pedel the idle cable and on the throttle body by the idling screw

Similar thing happened to me, but it ended up being a clutch on its last legs....Since you have an automatic, I'd guess its your Mass Air Flow sensor or throttlr body.