Game acts weirdly during "Lure" mission, then crashes...

[EL3GYFighter]

So, I decided to play through GTA IV once more as I haven't played that game in a couple of years.

 

Game has been running very well thus far, but I am currently trying to do the Mission "Lure" for Francis, where you have to snipe the Guy in his Apartment. Now ONLY in this Mission, not in any other Mission I can go to, the Game acts very strange.

 

Once I get to the Roof on the other side of the Apartment, from where you have to snipe, the Game starts to lag badly, like VERY badly. Which can't be, because my PC is strong enough for the Game to run at 1080p and around 40-60FPS on the Highest Settings possible (I don't know if it's the Optimization or my Hardware, or the ENB I'm using), which it has been doing steadily up until this Mission. Afterwards, once I try to shoot the Guy by luring him to his TV through shooting the Satellite Dish, the Game suddenly runs normal again, but once my Target checks his TV and I have my sights on him, the Game freezes. It happens EVERY single time.

 

If this is any help, I downloaded the Game from Steam with it's 1.0.8.0 patch and the removed Music, then I did this "trick" where you can download the pre-Music removal Files through Steam's Console. Afterwards after adding back the Music I downgraded to 1.0.7.0, because I wanted to use the CryENB 3.0 mod to give the Game a fresh look.

 

And this is how I started my playthrough. As said, has been going well thus far, but this Mission is bugging out.

Edited June 24, 2018 by EL3GYFighter