# Sporadic RPM increase

**URL:** <https://community.cartalk.com/t/sporadic-rpm-increase/72075>\
**Category:** Maintenance/Repairs\
**Created:** [April 24, 2012, 5:13am UTC](https://community.cartalk.com/t/sporadic-rpm-increase/72075 "2012-04-24T05:13:55Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Metalica](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@Metalica](https://community.cartalk.com/u/Metalica)\
**Post date:** [April 24, 2012, 5:13am UTC](https://community.cartalk.com/t/sporadic-rpm-increase/72075/1 "2012-04-24T05:13:55Z")

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I have a 2000 Volkswagen Jetta. For the past 4 months the car sporadically increases the RMPs. It could happen while driving or when stationary. It usually revs the engine to about 3,000. Normally, turning off the car when stationary fixes the problem. However, if the engine is not turned off, the engine will decrease its RMPs after about 5-10 seconds. The frequency of this problem has been increasing. What is the problem with this car?

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**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\
**Post date:** [April 24, 2012, 4:19pm UTC](https://community.cartalk.com/t/sporadic-rpm-increase/72075/2 "2012-04-24T16:19:59Z")

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The first thing that I would check is the Mass Airflow Sensor (MAF). It may need cleaning, or it may need to be replaced.

Another possibility is a vacuum leak, but in the case of a vacuum leak, the RPMs would fluctuate constantly, rather than sporadically.

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**Author:** ![mleich](https://avatars.discourse-cdn.com/v4/letter/m/71c47a/32.png) [@mleich](https://community.cartalk.com/u/mleich)\
**Post date:** [April 24, 2012, 4:23pm UTC](https://community.cartalk.com/t/sporadic-rpm-increase/72075/3 "2012-04-24T16:23:21Z")

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Check engine light on? Codes?

Does the engine actually rev up to 3000 or does the tach malfunction?

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**Author:** ![Metalica](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@Metalica](https://community.cartalk.com/u/Metalica)\
**Post date:** [April 24, 2012, 11:16pm UTC](https://community.cartalk.com/t/sporadic-rpm-increase/72075/4 "2012-04-24T23:16:28Z")

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The check engine light also sporadically comes on but it doesn’t always correlate with the engine revving up.

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**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\
**Post date:** [April 25, 2012, 1:12am UTC](https://community.cartalk.com/t/sporadic-rpm-increase/72075/5 "2012-04-25T01:12:37Z")

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Have the fault codes downloaded and post them here. Many parts stores will perform this service for free.

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**Author:** ![Metalica](https://avatars.discourse-cdn.com/v4/letter/m/cab0a1/32.png) [@Metalica](https://community.cartalk.com/u/Metalica)\
**Post date:** [April 25, 2012, 7:05am UTC](https://community.cartalk.com/t/sporadic-rpm-increase/72075/6 "2012-04-25T07:05:32Z")

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Great! Thank you. I will do that and get back to you.