I have a 1999 dodge ram 1500 4x4 when ideling it runs good for a bit at about 1000 rpm then surges up a little then back down, sometimes down then up, I have changed several things, plugs, wires, rotor cap button, fuel unit, fuel tank is supper clean, coil. Iac, map and have to no avail found any vacum leaks around the intake, please someone help!

There is one vacume hose that goes to the back of the intake right near the fire wall and it has a 90 rubber elbow that can rot out and give you a leak check it out that might be it, also i have replaced a couple of computers in these

I would recommend that you replace the TPS (throttle position sensor), as it will cause this issue. You might try cleaning the throttle body itself, if the butterfly is corroded, or the throttle body is dirty it can cause this as well. I had one doing the same thing, and yesterday I used a can of throttle body cleaner and it cured it.