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Engine idles too high?

Tiny
HOYT
  • MEMBER
  • 2009 CHEVROLET SILVERADO
  • 53,000 MILES
I just recently had exhuast put on my truck and I put a cold air itake on. Since it has beEn reving up to about 2,000 rpm on start up and when I rev it up and it stays at the higher rpm for a few seconds and while driving it does the same Thing until you get to a stop or slow down. I was told that the sensor just needed to adjust to the new air flow cause of it getting more air. Its been 2 weeks since I installed it and its still doing. I have tried disconnecting the battery to see if the computer would readjust to it and it hasn't. Please help! Thank you. Oh it has the 5.3 litre engine with the v4 mode
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Saturday, April 6th, 2013 AT 2:12 AM

41 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,916 POSTS
The relearns you're referring to also include short and long-term fuel trims. The short-term fuel trims, (STFT) is a set of data points that modify fuel metering right now to achieve a perfect mixture. You will rarely notice when those have been erased because they begin to update as soon as you start the engine. When the computer sees it's always making the same corrections for the same set of conditions it moves those numbers to the long-term fuel trims, (LTFT). Those are what it starts running off of each time you start the engine. As an example of the things it looks at, if you do get more air to go into the engine the computer is going to add more fuel. Now it will see a higher than expected idle speed with no corresponding change in throttle position sensor reading. It will be confused if it can't reconcile the higher speed to the closed throttle.

This guide can help us fix it

https://www.2carpros.com/articles/engine-idles-too-high

Please run down this guide and report back.

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Saturday, April 6th, 2013 AT 4:40 AM
Tiny
JEFFBROWN1966
  • MEMBER
  • 2 POSTS
  • 2006 CHEVROLET SILVERADO
  • 115,000 MILES
2006 chevy silverado 5.3 will not idle down untill you stop I used the seafoam spray in the intake through the front of the throttle body like it said to I also removed the throttle body cleaned it and changed the plugs, it idles fine and runs fine it is like the throttle is sticking untill you come to a stop then it just drops to the correct idle
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Thursday, June 18th, 2020 AT 1:18 PM (Merged)
Tiny
PROTECH1980
  • MEMBER
  • 901 POSTS
Is this a throttle acuated control module? Or does it have a throttle cable? If it is the throttle by wire system, which is failure prone, I would check with your local GM dealer about getting the pcm reflashed with the latest calibrations which they have come out with to address certain throttle related issues.
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Thursday, June 18th, 2020 AT 1:18 PM (Merged)
Tiny
JEFFBROWN1966
  • MEMBER
  • 2 POSTS
This is a computer acuated throttle there is no cable.
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Thursday, June 18th, 2020 AT 1:18 PM (Merged)
Tiny
PROTECH1980
  • MEMBER
  • 901 POSTS
If it is the throttle by wire system (has throttle acuated control module), which is failure prone, I would check with your local GM dealer about getting the pcm reflashed with the latest calibrations which they have come out with to address certain throttle related issues.
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Thursday, June 18th, 2020 AT 1:18 PM (Merged)
Tiny
YVBRU08
  • MEMBER
  • 1 POST
  • 2006 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 42,000 MILES
My husband drove his truck to work this morning and when he went to go get lunch, the truck started up fine and he drove over to the gas station. When he started up the truck to leave, the engine wouldn't rev up, it justs idles. He couldn't get it to do anything else. Is this electronic- or is it mechanically connected to the trottle valve, what are your thoughts?
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
DENNYP
  • MECHANIC
  • 1,824 POSTS
It is an electronic throttle control system. There is most likely a trouble code stored in the system. It is probably operating in reduced power mode.
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
BDWILSON
  • MEMBER
  • 5 POSTS
  • 2001 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 107,000 MILES
At start up it idles fine but after driving for 20-30 minutes it starts to idle at about 1000-1500, I can kill it for about 20 seconds start it and it idles fine for just a little while then back to high idle. What could be causing this? I also have aftermarket remote start could this be causing the problem?
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Is it setting a check engine light? Your IAC (idle air control) might be sticking.
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
BDWILSON
  • MEMBER
  • 5 POSTS
No it is not giving a code, is the idle controller repairable or do I have to replace it?
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Replace it. But if I was you I would go to the local shop and have them scan it. Sounds like a sensor could be telling it to raise up. Or like I said the IAC could be doing it.
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
BDWILSON
  • MEMBER
  • 5 POSTS
Is the IAC the small wire looking device inside the air intake tube? If so I sprayed some carb cleaner on that abouta month ago, someone told me it would help with my gas mileage?
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Tip of advice, never never never spray carb cleaner on anything on a newer car unless a trained mechanic tells you to. Sounds like you sprayed the MAF sensor. That may be your problem. You are gonna have to have a scan tool to see what it is reading. And no that wont help with gas mileage.
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
BDWILSON
  • MEMBER
  • 5 POSTS
Thank you for all of your advise, I guess I need to quite taking advise from those self proclaimed mechanics : (
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
ACROT996
  • MEMBER
  • 1 POST
  • 2001 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 123,500 MILES
My truck accelerates properly up to about 40mph then it revs up to about 4500rpm but no acceleration. I let off the gas for a spilt second this allows the truck to accelerate again. Is there something wrong with my transmission or any ideas what could possibly be malfunctioning?

Andy
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
DENNYP
  • MECHANIC
  • 1,824 POSTS
Yes, you could have damaged the MAF sensor. The IAC is located on the side of the throttle body.
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Hi there,

Thank you for the donation,

I would be getting the transmission checked out as I feel that there may be a problem with a shift vale, a transmission specialist may pick this up with a road test, start here.

Mark (mhpautos)
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Thursday, June 18th, 2020 AT 1:20 PM (Merged)
Tiny
CJCT6773
  • MEMBER
  • 3 POSTS
  • 2000 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 188,000 MILES
When I start my truck for the first two to three minutes it runs terrible it will almost die out. Then it rev's up by its self. I have tried to figure it out but cannot. Please help.
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Thursday, June 18th, 2020 AT 1:21 PM (Merged)
Tiny
JIS001
  • MECHANIC
  • 3,411 POSTS
Do you have the electronic throttle or throttle with cable?
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Thursday, June 18th, 2020 AT 1:21 PM (Merged)
Tiny
CJCT6773
  • MEMBER
  • 3 POSTS
It has a cable.
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Thursday, June 18th, 2020 AT 1:21 PM (Merged)

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