I have a very very rough idle when IN gear

SAMUELTIETJEN

MEMBER
2001 HYUNDAI ACCENT
113,000 MILES

I have a very very rough idle when IN gear. The vibration dissipates by about 75% when I throw it into Neutral or Park. The vibration disappears entirely once the slightest bit of gas has been applied (that is, when in gear).

It's a pretty bad idle. Produces a vibration sound that sometimes hurts your ears. Once and a while, I can hear a sort of clanky noise from what sounds like the back of the car which is in rhythm with the vibration at idle. Also gone when gas is applied.

RPM speed are completely stable and calm regardless of being in N, D, or R. It runs just below 1,000. I have replaced plugs and wireset with no results. /: Any advice is appreciated

2001 Hyundai Accent 1.6 DOHC

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

Check to make sure none of the motor mounts or trans mounts are worn. They have rubber in them to absorb the vibration. Also, check to make sure there are no engine vacuum leaks that could cause the engine to run rough. Also, Check and clean the idle air control valve.

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Friday, December 21st, 2012 AT 9:34 PM

SAMUELTIETJEN

MEMBER
3 POSTS

Jacobandnickolas, Thanks for the advice. It's my first car so I don't know too much about cars. I took off and cleaned the IAC valve with carb cleaner, no results. At all. I don't know how to check for vacuum leaks. But wouldn't there be some sort of difference in the engine's performance if it had to do with that? My rpm idle speed is normal and doesn't move, temp is normal, engine performance is fine. Just this darn vibration at idle. All points to the mounts right? Those sound like something I can check myself, what about replacing them? I have a good set of tools/jacks/stands. Worth doing myself?

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Sunday, December 23rd, 2012 AT 6:54 PM

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

There are how to instructions on the homepage for looking for a vacuum leak. As far as the motor mounts, it could be the, I would hate to see you put the time and money into them if they are good.

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Sunday, December 23rd, 2012 AT 10:44 PM

SAMUELTIETJEN

MEMBER
3 POSTS

Yeah. My plan is to look for a vacuum leak, and if that's not it, to take it to a mechanic and have them check the mounts for me. I definitely don't want to replace them if they aren't bad. They look to be about $90 a piece, but maybe the trans mount is good and the engine mounts are bad, or the other way around. A mechanic should be able to tell me. Thanks again

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Sunday, December 23rd, 2012 AT 11:05 PM

JACOBANDNICKOLAS