truck ran good until I changed alternator
 

Ok here's my problem I was driving my truck and the battery light came on so I drive the rest of the way home on my brand new interstate batteries. I got the truck home and tested the alternator it wasn't charging so I removed the alternator and brought it to my local parts store where they tested it and it failed so I bought a new one and installed it finished buttoning up the battery cables and went into the truck to fire it up and it fired and stalled instantly and keeps doing that over and over. What could be causing this all I did was change the alternator nothing else??? It's a 2003 ford f350 6.0 with about 185k on the clock. New hpop, oil cooler, ficm,icp,ipr,egr deIete and so on. Any insight on this would be a huge help

Are u sure u wired exactly same as old one?

There is only 1 plug and one wire to the alternator it would be kinda hard to mess that up lol.

Some I have seen have multiple leads on output post, forgetting one made some issues till we found it on the farm truck. .

Are your batteries run down a lot and you are jumping it to start it? That can cause lack of voltage to ficm. Charge batts over nite, can't hurt.