Q: What should I do when my engine revs up and down?

You first want to want to make sure that all electrical connectors at the throttle body are dry, free of corrosion and dirt, plugged in and making secure contact, particularly if you removed any during the service. Make sure none of the terminals are damaged or missing. If the connections are all made and the uneven idling problem arose after the cleaning, but did not exist at all previously, obviously something has been damaged.

Among the possibilities in the area you were working in are the TPS (throttle position sensor), a vacuum leak, the MAF (mass airflow sensor) sensor and the IAC(idle air control valve). To avoid any unnecessary repairs, a mobile technician, like one from YourMechanic, can perform a diagnostic on your rough idle at your own location.