Yes there was a recall on many 01 and early 02 Xs for a fault in the resitor module in the accelerator ass'y you should be able to find it.The SES light comes on but not all the time. And the truck will drop to idle like I said every so often it just kinda does it there's not really a pattern to it
Spec is no more that 0.6" of movement without engine RPM increase as I recall.
Have Dealer check your Oasis and see if your truck falls into this group and if the recall was ever done one it.
My 02 failed just prior to the recall but late enough that I did get the improved part, it would do exactly as you say, kind of scarry near the end of the on ramp!