Intermittent spark

Hi, I washed the engine bay down to clean it. Was running fine beforehand. Since then it is not running. I have cleaned every wiring joint and also sprayed them with a water dispenser it has also now been three days and everything is thoroughly dry. The car turns over on the starter and sometimes will fire very briefly but not start. I have now replaced the crank sensor thinking it was that but it made no difference. I also replaced the coil packs and leads I got from another wrecked one and that made no difference. If I take a spark plug out earth it and turn the car over it will spark very occasionally which is inline with the car firing occasionally but not starting. I must have a loose connection somewhere but just cannot find it. Tearing my hair out now. Any suggestions would be very much appreciated.