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Unread 05-02-2013, 07:38 PM   #1
doc8669
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2002 WJ 
 
Join Date: Apr 2013
Posts: 53
Need some advice

I have a 02 GC overland 4.7L H.O V8. Lately when I start it up it, the Rpm's go up and down between 1000 and 1500 when idling. It's almost like I'm giving it quick shots of gas but I am not touching the pedal. Eventually it goes back to around 600-800 Rpm's. What do you think causes this?

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Unread 05-02-2013, 08:05 PM   #2
car5car
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Join Date: Apr 2007
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Posts: 427
Broken breathers.
http://www.ebay.com/itm/MOPAR-Crankc...202661&vxp=mtr
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00 WJ 4.7 4x4 Limited
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Unread 05-02-2013, 08:05 PM   #3
doc8669
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Posts: 53
Quote:
Originally Posted by car5car
Broken breathers.
Can you elaborate on that please?

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Unread 05-03-2013, 07:51 AM   #4
metalhead
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How long does it take for the idle to come down? Mine does the same thing at first startup but after 30 seconds or so it comes back down to normal. Check the iac and tps sensors. If there is carbon buildup on the iac sensor or in the throttle body clean them.
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Unread 05-03-2013, 06:20 PM   #5
doc8669
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2002 WJ 
 
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Quote:
Originally Posted by metalhead
How long does it take for the idle to come down? Mine does the same thing at first startup but after 30 seconds or so it comes back down to normal. Check the iac and tps sensors. If there is carbon buildup on the iac sensor or in the throttle body clean them.
Yeah it doesn't take too long. Within a minute of so and it goes back to normal. Been working so much haven't had any time to do any work on it. Where is the tps sensor located on a 4.7L H.O? This is my first jeep and not familiar with the engine yet.

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Unread 05-03-2013, 06:24 PM   #6
ZJPunk98
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Location: North Kingstown, Rhode Island
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in addition, check your map sensor and the voltages on your o2 sensors. These all contribute to your idle control.
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