Ranger bucks at low speed

[Ramzilla]

Needing some advice please
1987 Ranger 2.9L 5 speed
Truck runs fine idling and going down the road but in parking lots at low speed or riding in the farm in 4 lo it will surge and buck badly. If barely on the accelerator holding steady it will sometimes just accelerate for lack of better terms.
I have swapped in a new IACV, TPS sensor,map sensor,checked ignition timing and checked for vacuum leaks. Air filter and fuel filters are new. Any help is greatly appreciated.

 

[powerranger262]

when is the last time your plugs/wires were done?

 

[Ramzilla]

About a year ago when I put the heads on. And it could be a wire issue I guess but the way it feels isn't really like a miss it is more like you are hitting the gas and then letting off over and over. But I am up for any suggestions right now it is really annoying when trying to ride a trail.

 

[Ramzilla]

Any other thoughts on this fellas? Oxygen sensor a possibilty?