Transmission

Take it to a parts store like Autozone or Pep Boys and have the codes scanned. By "jump", I presume you mean something similar to a horse bucking? That sounds like it might be a problem with the transmission control unit or the transmission itself.

As for the low oil issue, if the outside of the engine is dirty, you should clean it thoroughly so you can have abetter chance of seeing where the oil is leaking. Or you can buy a fluorescent leak detector fluid that is added to the engine oil. Drive the truck as normal for a day or so and then run a black light over the engine to locate the leak. If nothing shows up, the leak is internal and the oil is being burned.