I have built a slime block car using slime blocks, 2 pistons, 1 sticky piston and 2 red stone blocks (simple engine configuration found all over the internet). I have built it many times in the correct configuration, but when I try to activate it by adding the third redstone block (that I will later remove to let the thing take off into the sunset) only the piston directly below the redstone block fires. therefore, when I remove the activating redstone block the piston just retracts and that is the end of it.
All the videos on line show the pistons repeatedly opening and retracting (following the removal of the activation redstone block) but there seems to be a difference with my game as the diagonally positioned pistons do not react to the redstone blocks (i think that is the difference)