So, my 16 year old was driving his 2000 4Runner (V6 Automatic) today at HWY Speed going up a grade with Overdrive off. His friend in the passenger seat accidintly bumped the floor shifter into neutral, my son said he realized pretty quick and popped it back in drive. At this point the engine started vibrating badly and he drove about 200 yards to turn out and pulled over. (so the story goes)

I drove to the car and confirmed that when I start the engine it shakes badly and the Oil Pressure light comes on at idle. When I step on the peddal and rev the engine the light will go off but engine still very rough. I had it towed to a mechanic, however inittially they don't know what it is. Oil level good, well maintained and was running perfect prior to this. No smoke, knock or sign of oil leak or obvious issue.

Any help would be greatly appreciated.

bmed250

Sounds like maybe part of the story is missing. Going from Drive to Neutral and back shouldn't be a problem.
You may want to see if any CEL codes have been set.
An engine problem like you describe should trigger something.

Story checks out. I picked kids up on side of hwy, and gave them immunity for the accurate story. I wonder if it jumped the timing or something. Took it to Toyota dealer today, hope to know more tomorrow.

Haha "gave them immunity for the accurate story"

Yeah, this is strange. Hopefully it's nothing too serious.

Did they check the oil pressure in the lines/block? Its possible that in the time your son took to react the engine over revved without any load enough to cause an oil pressure issue?