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  #1  
Old 01-07-2016, 10:59 AM
hboyer90 hboyer90 is offline
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Default Engine RPMs spike when idling.

Hey guys I just bought a 2011 Ranger Sport with the 4.0 V6 36,000 miles.

The truck drives great, no problems at all. I just had a question if this is normal. When I'm idling the RPMs are right at about 750, and sit there nicely. When I turn the air it seems to spike up to 900rpms every 15-20 seconds. It will jump up to 900 for about half of a second and then come right back to 750. It never drops down below 750 and doesn't go above 900.

It feels like when you turn on the A/C and the compressor kicks in. But I'm not using A/C, I just have my heat on, blowing on my windshield/defrosting setting.

Is this normal? I normally wouldn't be concerned, but I just bought the truck and its still under a warranty.

It might be a dumb question but I just want to make sure it's normal.

Thanks!
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  #2  
Old 01-07-2016, 01:13 PM
jsz20102 jsz20102 is offline
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Default

Quote:
Originally Posted by hboyer90 View Post
Hey guys I just bought a 2011 Ranger Sport with the 4.0 V6 36,000 miles. The truck drives great, no problems at all. I just had a question if this is normal. When I'm idling the RPMs are right at about 750, and sit there nicely. When I turn the air it seems to spike up to 900rpms every 15-20 seconds. It will jump up to 900 for about half of a second and then come right back to 750. It never drops down below 750 and doesn't go above 900. It feels like when you turn on the A/C and the compressor kicks in. But I'm not using A/C, I just have my heat on, blowing on my windshield/defrosting setting. Is this normal? I normally wouldn't be concerned, but I just bought the truck and its still under a warranty. It might be a dumb question but I just want to make sure it's normal. Thanks!
ac kicks on in defrost to dehumidify the air it's a normal thing
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  #3  
Old 01-07-2016, 11:47 PM
driveit driveit is offline
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Default Re: Engine RPMs spike when idling.

Sometimes it may caused by a bad o2 sensor.
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  #4  
Old 01-08-2016, 01:23 AM
edanner717 edanner717 is offline
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Default Re: Engine RPMs spike when idling.

Quote:
Originally Posted by jsz20102 View Post
ac kicks on in defrost to dehumidify the air it's a normal thing
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