I have Episodes from Liberty City, standalone not DLC.

 

Whevener I start TLaD the game works fine, no errors, no crashes or anything at all - it just works as it should.

When I start TBoGT and Luis goes outside it crashes to desktop. I have tried teleporting elsewhere using the trainer but the result is the same, if Luis is outside I cant play.

I am guessing this could be down to a vehicle in a parking spot that is corrupted or something. Is there a way to fix this?

 

The save game is my own progress, it's not downloaded from anywhere.

Well, I'd recommend you to delete your save file and if that doesn't work, reinstall.

The save game files for the PC sometimes bug out by themselves causing them to not work. I've always had this error while trying to play the campaign on the PC. I would do as yard1 said, delete the save game file.