without warning my D90 while running down the road, highway, or other will sometimes loose partial power. So far i cant find any pattern of conditions that warrant this. Further more, she'll will also loose all power completely, to the point the engine dies. Electrical power seems to remain throughout.

On partial power loss, say 30%, when i turn the car off and on again, problem solved for the moment anyway. when it will happen again is anyone guess.

The same goes true when i loose engine power altogether, there is no signs forewarning of what is about to happen......it just quits. Now i can try to start it again immediately but she wont turn over. This is important.....only when i disconnect the computer under the passenger seat and quickly reconnect it will she start right back up with out fail. starts first time every time. There are no warnings lights on the dash, nor a check engine light that lights up.

honestly weirdest thing ive encountered yet.......im sure theres more to come with this truck.

any ideas?

You have a 4.0l V8 don't you?

no actually a 3.9l V8......why do you assume i had a 4.0? is random loss of power common on a 4.0?

3.9 or 4.0 isn't a lot of difference Mines a 2,495cc not a 2.5 at all

Anyhoo... when were the plugs and leads last changed and what plugs and leads were fitted? El Cheapo leads on these engines isn't a good idea and a bit of a false economy. The running at 70% power output sounds like limp mode.

The complete loss of power and failing to restart isn't just limp mode... not heard of that one before - this lot might be more use to you:

Land Rover Forums - Land Rover Enthusiast Forum

...as they're US based and will have the same model engine you have. 'Disco Mike' is probably the fella to speak to over there.

Cheers,