You can do this with the engine running but you'll probably get better results soaking a rag witb TB cleaner and wiping the plate and the area in the housing around the plate. Spraying cleaner with the engine running will, however, clean further down in the intake but that is not what is causing the sticky pedal.
I just did this job last week, it'll take you an hour with only a screwdriver and small metric sockets/wrenches.
