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Fluctuating Idle issue

Tiny
GURMEET
  • MEMBER
  • FORD CONTOUR
Greetings,

I have an issue with my 98 contour. At idle the car will jump from 1krpm to 1.2krpm then back to 1krpm again. It does this in a timely fashion almost every 30 seconds, any ideas?

Thanks
Thursday, December 7th, 2006 AT 1:09 PM

12 Replies

Tiny
WYNRYPEN
  • MEMBER
  • 52 POSTS
Dude, the year and the miles?
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Thursday, December 7th, 2006 AT 1:28 PM
Tiny
GURMEET
  • MEMBER
  • 8 POSTS
Sorry, 1998 approx 180 000 km
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Thursday, December 7th, 2006 AT 1:36 PM
Tiny
BRUCE HUNT
  • MECHANIC
  • 3,754 POSTS
Surging is caused by a sensor getting confused by an unusual condition is can not deal with and thus dumps fuel to try and compensate. Caused by vac leak, intake manifold leak, air in the cooling system, etc.
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+1
Thursday, December 7th, 2006 AT 1:40 PM
Tiny
GURMEET
  • MEMBER
  • 8 POSTS
Thanks for the tips, is there a sure way to test what might exactly be the issue? Could it be that the throttle body needs cleaning?
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Thursday, December 7th, 2006 AT 1:45 PM
Tiny
BRUCE HUNT
  • MECHANIC
  • 3,754 POSTS
Start with the simple ones of air in the cooling system and a vacuum leak on the engine. Check the vac hoses for a leak.
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Thursday, December 7th, 2006 AT 1:47 PM
Tiny
GURMEET
  • MEMBER
  • 8 POSTS
Did some basic troubleshooting, found that when and only when I have the defrost cycle on I get the surging, could it be the AC?
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Monday, December 11th, 2006 AT 6:40 AM
Tiny
BRUCE HUNT
  • MECHANIC
  • 3,754 POSTS
Isn't the A/C a switch away from being turned off. Is so, turn off the air and run the defrost. See if that narrows it down.
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Monday, December 11th, 2006 AT 8:36 AM
Tiny
GURMEET
  • MEMBER
  • 8 POSTS
They are not seperate controls. When I select defrost I can hear the AC turn on. At this time is when the engine surges. If I select panel vents or panel/floor there is no surging only when I select defrost is there a surge.
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Monday, December 11th, 2006 AT 9:46 AM
Tiny
GURMEET
  • MEMBER
  • 8 POSTS
The ac automatically comes on when I select defrost Appreciate the help.
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Monday, December 11th, 2006 AT 9:48 AM
Tiny
BRUCE HUNT
  • MECHANIC
  • 3,754 POSTS
I am unclear about which way to lead you on this. But I know that the ECU is unclear about the step up it must do to compensate for the pull down caused by the ac kicking in. Can someone else chime in if there is a sensor that is responsible for monitoring the ac?
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Monday, December 11th, 2006 AT 10:22 AM
Tiny
CARUNDELL
  • MECHANIC
  • 602 POSTS
Hey gru,
Your A/C will come on with defrost setting as its used to "dry" the air that blows on your windshield to remove any condensation faster. As to bruces question, several sensors monitor the A/C HP and LP Switches, also if the ac controller is automatic (electronic) it will control some aspects of the a/c compressor. Hope this helps

Regards,

Chris
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Monday, December 11th, 2006 AT 10:47 AM
Tiny
GURMEET
  • MEMBER
  • 8 POSTS
Do I have no choice but to take my car to a shop a have a diagnostic check done on it. Is there anything I can do my self?
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Tuesday, December 12th, 2006 AT 10:36 AM

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