In park or idle it sometimes revs and then idles low on 1999 Nissan Altima

Sometimes in Park or idling at a stoplight my car revs up and then down without my touching the gas, what's going on?

Asked by for the 1999 Nissan Altima
There are several sensors that can cause this, or a vacuum leak, or an issue with the idle controls. Is the check engine light on?
Yes
All the time in Park or idling at a stoplight my car revs up and then down without my touching the gas, what's going on? And the check engine light is on

2 answers 2 comments
Get the diagnostic codes in the engine computer checked and diagnosed.