A belated thanks for the replies here! I had seen a couple of replies via some sort of push notifications on my phone, but didn't realize there were so many posts here. I am still learning how the forum mechanics work.
Unfortunately, I am returning because this problem has reoccurred. Back when I initially posted, I was able to get the truck to my mechanic, who fiddled with the injector and the problem basically went away. He is not a diesel or land rover specialists and couldn't really tell me what he did. He approached it as a "tuning" service and adjusted the idle stops and I believe rotated the injector pump forward to improve timing. By the time he was done with that and got it started again, the problem had gone away. He did note some minor fuel leakage coming from the injector and recommended replacing the injector. I took the truck back and started looking for a replacement injector, but wasn't able to source one, meanwhile everything was working, so I sort of just kept driving and forgot about it.
The problem restarted about a week ago and is now occurring pretty consistently. The engine starts runs normally for about a minute and then starts randomly spiking to almost full RPM without any input on the throttle.
I am concerned that I am burning oil and could have something serious like a head gasket failure. I am seeing some oil leakage pushing out on the side of the block.
Is there a way to isolate whether this is an injector problem or something in the engine?
I am going to check the solution Ignotus suggests above, but would appreciate any other thoughts or suggestions.
------ Follow up post added March 24th, 2016 01:07 PM ------
Originally Posted by Capt Milks
When the engine goes to over rev can you use the key to turn it off?
Yes, you can use the key to cut it off. It takes a second to spin down, but it does cut off.