We got another thread named "truck dies when put in gear"
http://streetsourcemag.com/forum/topic.aspx?method=reply&topic_id=89511&forum_id=19&forum_title=&M=False&S=True
Do you have the CPI 4.3 because I just bought a Jimmy and its givin me the same issues? Go check out that forum cuz some people give some suggestions.