1999 Chevy S-10 Hesitation

Sounds like throttle position sensor (TPS). You can check it with an ohmmeter to see if it's nice and smooth throughout it's range.

I am pretty handy with a DIMM, What kind of resistance should it read? I will go get it off my truck tonight and check it out.

With the DVOM you're looking for a smooth rise and fall of the resistance. For some reason I can't bring up the pin connections and ohm readings. I'll try again in a bit. Attached is the voltage readings.

I checked and I do have a bad spot in the TPS. However I also hooked up a fuel pressure testor and when I prime the pump, I get 60psi. Then when the pump shuts off, it drops to 0 psi real fast.

You've got a bad regulator. It shouldn't go over 42lbs and not drop below 30. Over time it may bleed down, but not drop instantly.

Are you sure about the 34 psi? I have found many sources that say 60-66 psi. Also, how can I rule out the checkvalve in the fuel pump?

I stand corrected. On the 4.3, 5.0 and 5.7, it IS 60 to 66 lbs. I don't know what I was looking at. Forgive me.
When you hit the key the first time does the gauge jump right up to 60 lbs?

Yes it jumps right to 60 psi. Actually, I replaced the TPS, and it was bad, but it did not fix the problem. I also decided to clean the MAF. It Fixed the problem. I still think there is a problem with the fuel system not holding pressure but It runs good and I will address the fuel problem if it starts causing problems.

Thank you for your help!!!!!!!

The specs show the fuel pump pressure not to go below 30 psi on the 2.2 and the 3.4. On the 4.3, 5.0 and 5.7 it doesn't give any specs for shutdown pressure. But, as long as it "jumps" to 60 psi, I'd say you're ok.

Replace the fuel pump. Alldata and Mitchell say the pressure should be between 60-66psi. Actually it needs to be much higher. More like 90psi.