I would assume you have a check engine light as well. Press 'Info' up, and 'on/off' to enter diagnostics, use 'Info' to scroll alphabetically to PCM. Press 'on/off' and then use info to get 'PCM codes?' And press 'on/off'. Record and report code(s). It sounds like you may have an ignition misfire. Could be a plug, wire, coil, or related.