@blazejGBP
There are no hacks for GTA 4
But you can use cheat codes
Enter these into your phone to activate them
Change weather 468-555-0100
Get a different selection of weapons 486-555-0150
Get a selection of weapons 486-555-0100
Raise wanted level 267-555-0150
Remove wanted level 267-555-0100
Restore armour 362-555-0100
Restore health, armor, and ammo 482-555-0100
Song information 948-555-0100
Spawn a Cognoscenti 227-555-0142
Spawn a Comet 227-555-0175
Spawn a Jetmax 938-555-0100
Spawn a Sanchez 625-555-0150
Spawn a SuperGT 227-555-0168
Spawn a Turismo 227-555-0147
Spawn an Annihiliator 359-555-0100
Spawn an FIB Buffalo 227-555-0100
Spawn an NRG-900 625-555-0100
The cheats get saved into your phone so don't worry about having to constantly type them in or remember them