Before I talk about the main problem, I have a legitimate 2-disc copy of the game GTA 4: EFLC. If that's not enough, I can provide you the picture of the game packaging with the discs inside etc. etc. to prove that I have a legitimate copy of the game.
Ok so the first time I've done this mission everything loaded fine and I got into the third car and kept up with Mori until that ramp jump which I completely messed up and my car slid into the water. I got quite frustrated so I quit the game but went back to it a few hours later and that's when the problem began. I load up my savegame, ride a taxi to Mori's mission marker, drive to the place where the cars are stored then wait forever in the loading screen. There seems to be no memory problem whatsoever. System memory usage is only at ~67% and CPU usage at ~80% when running EFLC.
If my pc specs are necessary to solve the problem then here it is:
OS: Windows 7 Ultimate
Processor: Intel Pentium Dual Core E2180 @ 2.00GHz
Display card: GeForce GT630 2GB SDDR3