Surging at 1,500-2,000 RPM

[NVR2FST]

Does anyone have any ideas? While driving down the road at lower RPM's, the truck likes to surge/ stumble a bit. Seems to be doing it under harder accelleration as well.

It has 103k on it. Here is what I've changed trying to get rid of it:

- Plugs/ wires
- Fuel filter
- 02 that was throwing a code
- Plugged EGR to see if that was it

I'm starting to wonder if it's the coilpack...how long do these usually last?

Any ideas??

Thanks!