Still not runnin great

[nn2004]

This truck is killin me. I have unplugged all the sensors and driven it, as well as the EGR system, and it all still runs the same. I increased the idle even though I know you're not supposed to, and it runs a little better. It only stumbles when it hits around 500 RPMs at idle in gear. I increased its idle to 650 in gear, and it does it slightly less. I regapped all the plugs to .035 instead of the .040 that they were at, and it ran great, still does run better. But now it seems to be very hesitant to accelerate. When accelerating from a light, it tends to jump. It'll accelerate slightly, then be steady, and then 2 seconds later it'll start accelerating again, and it keeps going. When it is cold, it runs fine, but once it reaches around 180 degrees, it starts doing this. It has been starting fine in the morning now, oddly enough. The timing chain seems fine since there is no play in the rotor when I remove the cap. The plugs look great also. They are AC Delco CR43TS plugs. Hope those are the right ones. Injectors spray fine. Anything else I am missing here? My only next two thoughts are that the timing is actually off, or fuel pump is dying when it heats up. I dont think it is the fuel pump since it has been doing this hesitation since I bought it, and I drove it 150 mountainous miles a few weeks ago, and it did great. Any ideas anyone? Thanks in advance, and sorry to bother everyone again.