I almost garauntee that the code is for a misfire on one or more cylinders. If you rushed after washing the engine the water that collects in the spark plug pits would not have enough time to get out and would provide a path for current to jump from the wires to the block without firing the plugs. As for false starts, your plugs are likely to be fouled now so you might want to change them. Last time I did something like this I ended up with new plugs, cap and rotor.