Not starting
 

I got 2006 dodge 5.9 when i put the key in it starts right up but dies seconds later try to start it again wont start just crank i bought new batteries for my key fob but still does the sane thing need some help.

Any CEL codes? I would double check battery in truck/ key. Sounds like a security feature

Well i tried the key i usual use and it starts and stYs running but if i use the extra key is does yhe start up and die thing

You need to have the other key reprogrammed for your truck- if it's not programmed correctly it will die as a "safety feature". I would try a local ACE/hardware store as most can reprogram these. The dealer will likely charge a bunch to reprogram it