Car Shutting off

My car got a tune-up not too long ago and I gave it an engine cleaning (with the machine from the inside, oil was comming out too dark). But for some reason, my engine shuts off when I stop. Could be at a red light, whatever. It will begin to tremble and then shut off. What can it be and what can I do?

Auto of manual? It might br your idle is set too low. Also, do you mean you power washed your engine bay?

engine bay cleaning? water got in the dizzy?