Automotive

Engine rpm fluctuating on cold start

  • Last Updated:
  • Feb 4th, 2018 12:33 pm
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[OP]
Deal Addict
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Mar 23, 2008
4052 posts
450 upvotes
Toronto

Engine rpm fluctuating on cold start

Hi, I noticed that on my minivan, whenever I turn on the car the engine slightly revs up and down by itself. The rpm needle is basically bouncing up and down. If I have it in drive and I'm pressing the break pedal, the car is actually trying to move forward, which caught me off guard for a brief moment. This only happens in the severe cold (like today) and only during the cold start. Once the car is warm the problem is gone.

Any ideas on what this might be?
5 replies
Deal Expert
Aug 22, 2011
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Year?
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Deal Addict
Feb 16, 2013
1565 posts
1323 upvotes
Toronto
Idle air control or similar.
May need cleaning.
....
Deal Fanatic
Jun 26, 2009
5014 posts
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GTA
Does it happen when the tank is almost full or almost empty?
Deal Expert
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Dec 23, 2003
16291 posts
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Toronto
Throttle body sensor or the throttle body may be dirty. Depending on the age, it would be a good idea to:

- Get the throttle body cleaned (http://www.canadiantire.ca/en/pdp/crc-t ... 0781p.html)
- Check the air filter to see if it is dirty
- Get the Mass Air Flow sensor cleaned (http://www.canadiantire.ca/en/pdp/crc-s ... p.html#srp)
- Put a bottle of some fuel cleaner just in case (http://www.canadiantire.ca/en/pdp/gumou ... 0163p.html)
Deal Expert
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Feb 11, 2007
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GTA
Clean Idle Control Valve (OCV, throttle body, throttle position sensor, check for vacuum leaks. Probably not MAF since it should be running in open loop at start up until the o2 sensors heat up.
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