heard this one yet????

[stevenfromtexas]

ok, i've been tweaking on my pickup for the last few months. when i'm out driving it, it will die when down shifting from 3rd to 2nd. this is a huge problem when i go to turn onto my street and down shift to turn left. it will die. not cool when there are cars heading toward me. most of the time i have enough momentum to pop the clutch and get it going again.
Also, it is making a "sucking" noise around 40MPH. i can ease into the accelerator and it goes away. just seems like it's starving for either air or fuel

so....why do you guys think this is happening.

250
3OTT
single barrel rochester
10* initial timing
RPM's approx: 550
Petronix ignition
full tank of gas

let me now if there is another info y'all need