have 2006 f250 6.0 was told my alternator was shot and needed 2 battery's put them in and today the truck wouldn't start had to boost then it started but when i removed the booster the truck would stall any ideas what is wrong

 

About half of life's problems require a volt meter to solve. Charge the batteries fully, then see if it'll run. If it runs, use the volt meter to see whether or not the alternator is working.