only studders/hesitates on acceleration when the engine is cold - really bad. once the engine reaches normal operating temps (190-210), it no longer hesitates on acceleration or it's not very noticeable (still trying to determine this). it seems to have a miss at idle when cold moreso than when hot. Any ideas? i changed the plugs, wires, cap, poppets and pressure regulator about 5,000 miles ago and just recently the fuel filter. thank you.

Any codes or check engine lights?
Has fuel pressure been checked?
Is the MAF sensor dirty?
What kind of plugs did you use?

Had the exact same problem on my 98 4.3. Change the cam sensor located inside the distributor. I actually changed the whole distributor with a junk yard one, but I'm pretty sure it was just the cam sensor.