Automotive

Engine rpm fluctuating on cold start

  • Last Updated:
  • Feb 4th, 2018 12:33 pm
Tags:
[OP]
Deal Addict
User avatar
Mar 23, 2008
4048 posts
441 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?
6 replies
Deal Fanatic
User avatar
Dec 28, 2007
7957 posts
4582 upvotes
Alberta
I had the same problem with my Mustang GT. The problem on mine was a bad throttle body position sensor.
Deal Expert
Aug 22, 2011
35645 posts
21730 upvotes
Center of Universe
Year?
Make?
Model?
Deal Addict
Feb 16, 2013
1560 posts
1298 upvotes
Toronto
Idle air control or similar.
May need cleaning.
....
Deal Addict
Jun 26, 2009
4049 posts
3113 upvotes
GTA
Does it happen when the tank is almost full or almost empty?
Deal Expert
User avatar
Dec 23, 2003
15368 posts
3695 upvotes
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)
Car Batteries - FAQ, General Information, Tips & Tricks

Car Buying Tips & Tricks

My Cell Phone Providers: Koodo Mobile and Zoomer Wireless
Deal Expert
User avatar
Feb 11, 2007
16496 posts
18049 upvotes
Oakville
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.
If the women don't find you handsome, they should at least find you handy.

Top