I don't have the engine running when I clean the throttle body. Have someone inside the car hold the throttle wide open, spray the cleaner onto the surface, gently brush (I use an acid brush from the hardware store, for spreading acid on a surface to solder, looks a bit like an art brush with a metal handle), gently wipe with a soft rag or soft paper towel, repeat as needed. Pay particular attention to the black carbon ring on the throttle bore just inside the throttle plate. Clean both sides of the throttle plate as well as as much of the bore as you can easily reach. Some cleaner will remain in the manifold so the engine will run a bit rough for a moment when you start it. You may need to hold the throttle wide open (to shut off the injectors) to start the flooded engine.
