Rough idle

Tiny
BEBA
  • MEMBER
  • 2003 HONDA ACCORD
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 65,000 MILES
Idle is rough(Low @ 500 rpm, Vibrate) if A/C on when the car stops at Red light. Idle is normal if A/C off (600 to 750 rpm). Could you please help to know what is the problem of my car.
Thanks you.
Beba
Sunday, August 15th, 2010 AT 2:57 PM

9 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi Beba,

The Idle Air Control valve and throttle body is dirty. Getting them cleaned should solve problem.

This guide can help

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

Please run down this guide and report back.
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Tuesday, August 17th, 2010 AT 11:14 AM
Tiny
WG4TIM
  • MEMBER
  • 2 POSTS
  • 2002 HONDA ACCORD
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 93,250 MILES
Where is the EGR valve located? My2002 Accord EX V6 has a minor rough idle issue and the exhaust smells almost as if it is flooding. I was told to replace EGR valve. Is this correct or do you think it is something different. Otherwise it runs great.
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Saturday, November 16th, 2019 AT 2:40 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi wg4tim,

Thank you for the donation.

Is the Check Engine Light indicating?

Is the rough idling occurring only at cold start?

The EGR is located at rear of engine on coolant passage.
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Saturday, November 16th, 2019 AT 2:40 PM (Merged)
Tiny
WG4TIM
  • MEMBER
  • 2 POSTS
Check engine light is on and rough idle occurs all the time. It runs fine while driving but as soon as you stop, the rough idle is always there. Advanced auto check codes should possible blocked egr passage or random misfire on a couple of cylinders. How do I locate egr if I need to change it also?
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Saturday, November 16th, 2019 AT 2:40 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
What are the exact trouble codes for the CEL?

A TSB was issued for the EGR for up to 2001 models and quite often a fault with the EGR requires more than replacement of the EGR valve. The EGR passage in the manifolds needs to be cleaned as well.

I will send the TSB to you, it has pocedures for cleaning the passages. Some steps might be omitted if yours is a 2002 models as some modifications had already had been done.

Random misfire occurring at idling could be due to ignition and fuel problems. Were the spark plugs checked?
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Saturday, November 16th, 2019 AT 2:40 PM (Merged)
Tiny
WERLIN1212
  • MEMBER
  • 1 POST
  • 2002 HONDA ACCORD
  • 4 CYL
  • 2WD
  • MANUAL
  • 197,000 MILES
2002 Honda Accord with 197,000 miles. Recently replaced plugs and wires. We narrowed down which cylinder was missing: ie (The only one where pulling the wire to the plug didn't make the idle more rough. Pulled that plug and it was dry/not fouled. Replaced all fuel injectors. Finally tested missing cylinder's fuel injector connector signal. It was weak. All other injectors had a strong signal. What should be fixed/ replaced to give a stronger signal to that injector? Do injectors require a certain minimum voltage to operate? I looked for awhile on the message boards but couldn't find this exact problem. Please help. Thanks.
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Saturday, November 16th, 2019 AT 2:40 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi Werlin1212,

All injectors receive the power from the same source and if the voltage is lower for one particular injector, check for bad wiring connections. The wires are spliced in the harness.

If it is the grounding circuit that is bad, you need to check the resistance to the PCM. If resistance are similar for all injectors, the PCM is the one causing the problem.
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Saturday, November 16th, 2019 AT 2:40 PM (Merged)
Tiny
PACEMAN2000
  • MEMBER
  • 1 POST
  • 2002 HONDA ACCORD
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 11,250 MILES
Here is my situation. I purchased this vehicle 2 weeks ago and it ran flawlessly. Engines was very smooth like a new motor. It had 112,000 miles on it and I decided to get a new timing belt and water pump, the typical routine. When I got the car back from my mechanic, I noticed the idle was rough and that it shifted funny from 1st to 2nd gear. I took it back a few days later so he could check it out. He did notice the rough idle and would look at it. He is a great mechanic and a very honest friend and insists he put the timing belt on correctly. I picked it up the vehicle a few days later and he told me that he checked the motor mounts and that they were good. He also did some type of memory check on the car so the cars computer could reset itself. I though this would alleviate the problem. I started it and the RPM stays at 1000 for five minutes then after that goes to 750. The idle is still rough in all gears of park, rev and drive. Whatever he did with the cards computer, the tranny now shifts smooth but the idle remains rough.
I also had him put in new NGK pugs just for maintenance. One more thing. The car almost stalled at a stop sign, gave it gas to keep it going. The car runs perfectly when driving, just at idle does it shake noticeably. Any suggestions?
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Saturday, November 16th, 2019 AT 2:40 PM (Merged)
Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
The new pugs could be causing your problem, however, it sounds like the throttle body is dirty, and the idle air control valve may be faulty
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Saturday, November 16th, 2019 AT 2:40 PM (Merged)

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