I've searched a bit and haven't found any threads that address this.

Truck starts fine. It idles fine in 4wd, but in 2wd, sputters and dies at low rpm, AND when I give it some gas. At higher rpms, it eventually evens out. Problem is less bad when engine is cold.

Shop says there aren't any vacuum leaks. Replacing harmonic balancer helped, but still pretty bad.

Any help with where I should start hunting....either on the truck or in threads here?

Truck has plenty of other problems that could be contributing, but I don't know enough to know which ones matter.

 

I am willing to bet you have a automatic Transmission Correct??

I don`t really see how a manual could cause this problem

Now if it was a newer vehicle with ADD I could see a vacuum leak when the shift lever was in 2wd.

which could be missed quite easy.

This is off the top of my head without checking .

 

Yep. It's an automatic.