I've read before that it was intended to be titled Cannonball Run 3. But when the Cannonball team (I presume Hal Needham?) saw the final result, he refused to allow them to use the name Cannonball as he thought it was not worthy of being an official sequel.
However, this is most likely internet B.S. As I don't think the name Cannonball Run can be copyrighted, as they hold the actual races around the world now and then. Unless Needham or someone DOES own the copyright to the name, and the actual races get his permission to use the title?
Either way, international laws don't seem to apply, as it is titled Cannonball Run 3 in Europe.

Oh god this is sad. It was just on TV here and i had at least hoped it was descent. But frankly it had none of the charm of the original movies. Its obviously a Cannonball run 3.
Take away the famous cast
Take away all the whacky humor
Take away the exotic cars
Its just a utterly waste of time.. Im deeply dissapointed.

The DVD, released in Sweden (in English), is named Cannonball Run 3.

"If I've never seen it before, it's a new release to me."

The large change i the overall cast had a lot to do with it, also, at the point of its release "Cannonball Run" was now a dead franchise and the title did little to excite audiences. This lead them to try out a new title, in the hope of giving the movie the shot in the arm that it neede after alread doing poorly with test audiences.

probbaly because no original casts were back for it even thought they explaineds that with the hotel bust that arrested everyone.