Idles rough and RPM's jump at idle.

Tiny
SERGEYEMT
  • MEMBER
  • 2003 DODGE TRUCK
  • V8
  • 4WD
  • AUTOMATIC
  • 88,000 MILES
Hello,

The problem I am having, is when the truck is rather in neutral, or I am standing at a red light with my foot on the break, the RPM's jump under 500, then up over a thousand, and they will continue bouncing up and down until I start driving, a few times the rpms fell low enough that the truck actually stalled, although restarted with no problem. It also seems to lose a little power at cruising speeds, requiring me to push on the gas harder to pass a car, and this causes rpm's to jump up fast. I got it tuned up, but the problem still exists. Could it possibly be the Idle Air Control, or the EGR Valve failure.

Thanks
Monday, May 25th, 2009 AT 11:44 AM

16 Replies

Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
Check for a vacuum leak as a 1st step also do a code check you can check and clean IAC too let me know
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Tuesday, May 26th, 2009 AT 5:03 AM
Tiny
WAIN ZAIN
  • MEMBER
  • 5 POSTS
Same truck but mines a 2500 hemi. Mines pretty rusty under there. Same issues and getting worse. What was the problem and your solution? My ac seems to have gone really warm during this issue as well. Texas heat. Probably just needs charging but I thought it may be worth mentioning or be connected. Thx, Zain
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Thursday, August 8th, 2019 AT 1:45 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,149 POSTS
The AC shouldn't effect the engine running. to me it sounds like the throttle actuator is dirty here is a guide to help fix it

https://www.2carpros.com/articles/throttle-actuator-service

Can you please shoot a quick video with your phone so we can see what's going on, that would be great. You can upload it here with your response.
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Thursday, August 8th, 2019 AT 10:35 AM
Tiny
WAIN ZAIN
  • MEMBER
  • 5 POSTS
Yeah sure. Thanks for the response
Video (Click to make bigger)
Thumb
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Thursday, August 8th, 2019 AT 7:54 PM
Tiny
WAIN ZAIN
  • MEMBER
  • 5 POSTS
I drove it all day today and it didn't act up one time. So strange
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Thursday, August 8th, 2019 AT 7:56 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,149 POSTS
Thanks for the video. We should run the codes also does it have the catalytic converter still on it? Sounds like you have an exhaust system maybe?

Lets do this guide next.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.
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Friday, August 9th, 2019 AT 12:36 PM
Tiny
WAIN ZAIN
  • MEMBER
  • 5 POSTS
No lights have ever come on. But I took it to O'Reillys anyways thinking that maybe the bulb was out on my check engine light. But I was told no light, no codes, no information.
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Saturday, August 10th, 2019 AT 5:23 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,149 POSTS
Lets start with a tune up and the throttle actuator service that way we can rule them out. also look at each plug to see if one is different coloring that the others which can indicate the cylinder that is giving us problems. Here is a guide to help us:

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

and

https://www.2carpros.com/articles/engine-vibration-at-idle

Please run down these guides and report back.
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Saturday, August 10th, 2019 AT 11:38 AM
Tiny
BILLN457
  • MEMBER
  • 4 POSTS
  • 2003 DODGE TRUCK
  • V8
  • 4WD
  • AUTOMATIC
  • 158,000 MILES
I have a 03 dodge ram 2500 5.7 hemi when I start it up the idle jumps up and down try's to stall and it dose stall sometime's and when I put it in to gear it runs rough for a few but come's out of it and run's fine until I shut it off when I start it again it starts allover again
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Saturday, August 10th, 2019 AT 2:16 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Engine running rough or misfiring can be cause by the following:

1. Defective spark plug
2. Inadequate spark/coil, defective spark plug wire.
3. Lack of compression
4. False air leakage.
5. Faulty fuel injectors.
6. Insufficient fuel pressure.
7. Contaminated fuel.
8. EGR valve that is leaking.
9. Oxygen sensors.
10. Throttle position sensor.
11. Idle air control valve.
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Saturday, August 10th, 2019 AT 2:16 PM (Merged)
Tiny
BILLN457
  • MEMBER
  • 4 POSTS
I have replaced most of the thing u have said but still dose the same thing
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Saturday, August 10th, 2019 AT 2:16 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
What was the reading on the idle air control valve and throttle position sensor-
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Saturday, August 10th, 2019 AT 2:16 PM (Merged)
Tiny
BILLN457
  • MEMBER
  • 4 POSTS
How would I get a reading on that stuff
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Saturday, August 10th, 2019 AT 2:16 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
I have replaced most of the thing u have said

What did you replaced? You need to troubleshoot all of it -don't waste your money throwing parts to it hoping it will fix it
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Saturday, August 10th, 2019 AT 2:16 PM (Merged)
Tiny
BILLN457
  • MEMBER
  • 4 POSTS
I have replaced plugs and wires 02 sensor sofar
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Saturday, August 10th, 2019 AT 2:16 PM (Merged)
Tiny
WAIN ZAIN
  • MEMBER
  • 5 POSTS
Same truck. Mines pretty rusty under there. Same issues and getting worse. What was the problem and your solution? My ac seems to have gone really warm during this issue as well. Texas heat. Probably just needs charging but I thought it may be worth mentioning or be connected. Thx, Zain
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Saturday, August 10th, 2019 AT 2:16 PM (Merged)

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