idle problem

92 s10 blazer,4.3 cpi,4x4. Stalls out in middle of driving. The motor idles up and down when stopped. Has no overall power. I have to keep my foot on the gas petal so it wont stall out. when it does stall out it takes 5 sec and a little push on the gas to get it started. Any info will help to point me in the right direction towards solving the problem.
thanx,J

complete tuneup, check fuel pressure, and all vacuum hoses for leaks. thats a good start.