Truck was left with the AC on, and engine off on several occasions. Losing the radio station presets was the first indication of a problem. Then the battery finally died. After installing a new batt tonight, it runs, but won't idle. It's like there's no lower RPM limit, and it just dies. Could a bad alternator cause that, or could the computer need a fault reset or something?

Thanks!!!!!

 

I had the alternator tested. It turned out the computer needed a 1/2 hr hwy trip to get reset properly. Truck's happy now