stall

I have a 1996 blazer 4wheel drive i just bout it a month ago so dont no if the fuel filter or any thing else was ever replaced i do no the fuel sending unit was replaced heres wat it did i started today and got it warm turned it off and about 20sec later stared it ran fine for 5sec and then almost stalled dident but close the check engine light did not come on and it runs great this the first time it has done this just wonding if any body else has had this and wat it might be causing im thinking fuel filter but just wanted your advice

How many miles on the Blazer; are you aware of any maintenance that has taken place??
If you bought from a dealer, they probably (but not definately) did some maintenance on it to bring it on the lot. If you bought from a private party, you can try and ask what has been done.
If you have no idea what has been done I would recommend checking out this thread in the FAQ section:
http://www.automotiveforums.com/vbulletin/showthread.php?t=453370
That is the general maintenance and tune up thread. Start with a tune up and fuel filter change. It will probably take care of your problem.