If you have used the Pedestrian Riot cheat, Madd Dogg will jump before you get a chance to rescue him. If not, take the truck and follow his movements. Position yourself in a straight line with him and you will catch him easiliy when he jumps. Blaze9713 says: If you used..i think..about 500 cheats in the game total or over, he jumps instantly, so either reload or keep ur finger on the accelerate button.