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Whitey
Dodge Dakota
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5/16/2005
15:29:34
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 Subject: Eratic idle
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Message:
I have an 02 4.7L with about 50,000 miles. Recently the idle is occasionally becomming erratic slowing to around 400rpm and immediatley revving back up to about 1000. It is driving me nuts. Can anyone tell me what might be the problem. There is no check engine light or trouble code. Thanks!
Here's my combo
4.7L Sport 4X4, manual trans, 3.92 RAR, K&N, 185 thermo, calibrated tps, superchips programmer, dynomax ultraflo exhaust, one heat range cooler spark plug
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DK
Dodge Dakota
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5/17/2005
00:12:57
|  RE: Eratic idle
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Message:
I had this problem a long time ago. It started when I first bought the truck and was intermittant after that-for thousands of miles! The dealer said it was normal, then one day error codes popped up. I forget the # and the name of the part(some help please)but it is easily replaced~$20 to $40. Sits right next to the air intake. I wish I had known sooner-seems the computer was thousands of miles off. Fixed the problem and no idle problems since.
2000 4.7 CC
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daffydak
GenIII
5/17/2005
00:34:08
| RE: Eratic idle
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Message:
My 00 4.7L does something similar (only after it's been sitting for sevral hours)
It will start and run fine at 650 for about 5 seconds, then it runs rough and almost dies (it has actually stalled when it was in gear and did this)
Then it revs up to about 1300 RPMs and the idle is fine afterwards... it almost acts like it's loading up with fuel... i can hear the IAC valve opening (the intake sound increases) as it's running rough..
Also if I tap the pedal as it's doing this, it has about a 1 second hesitation before it reacts to the input. It's really scary when it's in gear, and revs up on it's own like that... i have to really mash the brakes to keep her still :-( other then this, it runs like a raped ape! it idles smooooooth and runs up to redline without a hiccup..
I wonder if the MAP sensor may be causing this??it might be gummed up and reading low vacuum when it'd cold and over richens the mixture (you can smell it running rich when it runs rough) I really dont want to take my truck to the stealership, can anyone give me some insight??
Dan
MOPAR=More Power!!
00 CC Sport Plus 4.7L 4X4 Auto, 3:55 LSD
Flowmaster orig. 40 series (2 chamber) muffler, adjusted tps to .76V, ported TB, home brew intake setup w/K&N filter, Superchips 3715 Tuner more mods to come!!!
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Rob C
Dodge Dakota
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5/17/2005
00:43:37
| RE: Eratic idle
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Message:
Sounds like he's describing the TPS (throttle position sensor) or IAC motor (idle air control). However before you replace anything, you should remove and clean the throttle body thoroughly with carb cleaner. It's very easy to do and you should remove the IAC motor and clean the idle air port and the pintle on the motor. You don't need to replace the throttle body gasket because it's reuseable.
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01Motorsport
Dodge Dakota
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5/18/2005
00:31:21
| RE: Eratic idle
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I agree with Rob C; a dirty IAC motor and/or TB will really make the 4.7 act up. My favorite plugs for idle quality are Bosch 4418 platinum +4's. '01 RC 2wd 4.7 5-spd 3:92, HO cams, TB mod, homebrew air intake, Magnaflow y-pipe/3" cat/Flow 70 duals.
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Whitey
Dodge Dakota
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5/19/2005
10:25:36
| RE: Eratic idle
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Well... I checked out the problem thinking I was going to remove the TB and clean it. Before I started I decided to do a quick inspection of the IAS and TPS (connections, calibration ect...) All was normal and the TPS was calibrated just where I set it last year.
Turns out the 1/4" hose that comes off the TB right near the TPS had a couple of splits in it just past the fitting. I think it was sucking air. I cut the split ends off and put it back on. So far the idle is back to normal (2 days).
What is the function of that hose?
Thanks again to all those who replied.
Whitey...
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dakoter4.7
Dodge Dakota
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5/20/2005
01:59:22
| RE: Eratic idle
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Message:
i got an 03 that does the same thing only when its cold, i was guessin possibly coolant temp sensor issue
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