Erratic idle sometimes and other times drives fine.

Tiny
RANGERGIRL554
  • MEMBER
  • 2002 FORD RANGER
  • 100,440 MILES
I have a 2002 ford ranger, and when it is humid outside, it will not idle properly at times.I will crank it up, let it go through it's warm up cycle, and when I go to back out of my driveway the idle soars up to close to 2,000rpm's and so I usually have to pull back in and turn off the truck, and let it sit a minute, and then recrank it just for the idle to go down. And then other times, it runs perfectly fine, and idles the way it is supposed to around 600rpm's. This is driving me crazy, replaced the IAC, cleaned the throttle body and maf sensor, put a new air filter, change d transmission fluid, and oil about a month ago, and I have noticed when I am going to work sometimes that it sucks gas by the gallon, and then when I pull up to a red light, I notice the idle is high. What is going on?
Thursday, October 13th, 2011 AT 2:20 AM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,779 POSTS
Make sure the IAC is getting power. Also, check for vacuum leaks.
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Thursday, October 13th, 2011 AT 2:22 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Just to add, check the big hose from the throttle body to the mass air flow. It is common to crack and open allowing outside air in and giving you these symptoms.

Roy
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Thursday, October 13th, 2011 AT 2:27 AM
Tiny
RANGERGIRL554
  • MEMBER
  • 8 POSTS
Would the IAC be bad already? I mean I have had to replace it 5 times in the last 8 years, but for two years I was running with a vacuum leak and I never had any problem out of the idle until now
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Thursday, October 13th, 2011 AT 2:27 AM
Tiny
RANGERGIRL554
  • MEMBER
  • 8 POSTS
I just cleaned the air hose, throttle body, IAC valve and MAF sensor today and also installed a microgard paper filter instead of a K&N. It evened out for awhile, but I drove home and the idle was high
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Thursday, October 13th, 2011 AT 2:29 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Once again, the hose has to inspected for cracks and openings for air leaks. Did you do that?

Roy
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Thursday, October 13th, 2011 AT 12:31 PM
Tiny
RANGERGIRL554
  • MEMBER
  • 8 POSTS
We have inspected the hose, and just had to change the IAC motor today, when the truck idle revved above 3,000 rpms. It seemed to level out the idle for a while, but then it started jumping again, and so we are now going to disconnect the battery, and replace the TPS sensor and the PCV valve.
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Friday, October 14th, 2011 AT 1:00 AM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
Rangergirl554

MAYBE YOU ARE NOT BEING "AGGRESSIVE ENOUGH" (COMING FROM AN AIRBORNE RANGER)

EITHER OF THE 2 SUSPICIONS FROM J&N OR ASEMaster6371 SOUND PLAUSIBLE

MY 1ST THOUGHT UPON READING THIS WAS.A VACUUM LEAK

HOW ARE YOU CHECKING FOR ONE. PLEASE ELABORATE. WE MAY CAN HELP GIVE YOU OTHER WAYS.

AS FAR AS THE HOSE, TAKE IT OFF. RUN YOU A LIGHT DOWN THRU IT, COVER THE ENDS WITH RAGS. SORTA GENTLY TUG-A-WAR IT AND LOOK FOR LIGHT ESCAPING. IN A DARK ROOM

BE NICE IF IT WERE SOMETHING EZ THAT YOU HAVE MISSED

YOUR TURN

THE MEDIC
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Friday, October 14th, 2011 AT 1:20 AM

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