Don't run with the infinite ammo option constantly on. Just use it once, fire whatever gun you need max ammo with to get it up the 999 ammo and then turn it off. Then turn it on again whenever you need more ammo.
The only reason the trainer would actually cause crashes would be due to either the 999 item issue (more of a game engine memory leak issue) or you entered a casino and they needed to take your weapon but the trainer kept the infinite ammo option on so the trainer kept trying to give you back your weapon and conflicted with the game.
Otherwise, you're crashing because Bethesda/Obsidian can't figure out how to make stable video games.
I appreciate it man Thanks for the info
The trainer always seems to make the game itself crash a LOT. I cannot even sell/buy Items in the New Vegas area without it crashing. Anyone else been experiencing this??
Certin items you cant pic up with Unlim ammo. Cause it changes the amount for everything else. oddly caps to lol. So you need to like thingy said. Do not have it on all the time!