When Jimmy Fergus meets his father, Senator Johnny Fergus, he says "...and when that special water comes in...". The decision to spike the Washington, D.C. drinking water supply with LSD was made in the scene following this one during Max's War Council, so this scene with Jimmy and his father was edited out of sync.
When Max blows up his father's new car, he places the explosives on the front seat; however, the initial explosion occurs in the car's trunk. It can also be seen that the car's driver's side door has been deliberately rigged to just fall off.
When Max performs at the Fergus rally, his fretting fingers stay in one shape so that it's obvious he does not know how to play real guitar chords.