93 accord rough idle

car runs smooth when cold, when warms up it runs rough as if lean. EGR clean and closes any suggestions

Hm, could be vacuum leaks, spark plugs, possibly o2 sensors. Also when is the last time you checked your thermostat?

First thing you can do is to check if the computer has any error codes stored. Start from there.

My mechanic performed what he called an "induction service" on my '93, and it cleared up the rough idle. I assume it involved cleaning? I didn't ask him (my bad).

Is ur Accord an Automatic or Manual? If its an automatic it might have a vacuum controlled rear engine mount and when something in that system goes out you will get a rough idle. I know the 94 and newer Accords come with this rear engine mount for the automatic transmission Accords. The rod on my old rear engine mount broke then I bought a new rear engine mount and had it installed at the Honda Dealer and now my car idles nice and smooth :) The vacuum controlled rear engine mounts are designed to reduce idle vibrations.

when something in that system goes out you will get a rough idle.
Yeah, but it would tend to be WORSE when cold, not the other way round.

My mechanic performed what he called an "induction service" on my '93, and it cleared up the rough idle. I assume it involved cleaning? I didn't ask him (my bad).

Induction service:

A throttle plate cleaning and mixture adjustment, like I keep tellin' you all. But don't listen to me..... :grinno:

Induction service:

A throttle plate cleaning and mixture adjustment, like I keep tellin' you all. But don't listen to me..... :grinno:



you can adjust mixture on a 93?

Jeffcoslacker - can you?

Jeffcoslacker - can you?

Not sure. Haven't had to do that to Mom's '94 yet, and I don't remember any others I might have done. As a rule, the OBD I engines still have the screw on the throttle plate, but it is plugged with a freeze plug that has to be removed to access it.

Once you get to full feedback idle air bypass control (OBD II), there is no provision for it. Idle air mix is controlled solely by an IAC motor controlled by the ECM.

You'd just have to look and see if there is a cap where the screw should be.

Not sure. Haven't had to do that to Mom's '94 yet, and I don't remember any others I might have done. As a rule, the OBD I engines still have the screw on the throttle plate, but it is plugged with a freeze plug that has to be removed to access it.

Once you get to full feedback idle air bypass control (OBD II), there is no provision for it. Idle air mix is controlled solely by an IAC motor controlled by the ECM.

You'd just have to look and see if there is a cap where the screw should be.


tanks ill look

could there possibly be a sensor that is out of wack? i know that on my 86 Accord, the TW sensor went bad, and that caused a rough idle when it was hot, also it wouldn't start when it was hot. Just a thought.

Actually Codger i was looking at it as if he were saying his car was "cold" like wen u first start it and warm it up. There is cold wen u first start the car and warm it up. Then there is the first few miles of driving which can be called cold also. I was mentioning that if he was talking about his car being cold before it warms up for the first time. You know when your car is first warming up the rpms are raised and the idle wouldnt feel rough wen the rpms are raised. I mentioned the engine mount if he was talkin about that senario. You know and then when the car warms and the rpms reach regular idle speed then u feel the rough idle. thats what i was talking about. i know there are many possibilities for a rough idle. the #1 reason i always hear for a rough idle is vacuum leak. im not sayin thats ur problem tho. i think what jeff said sounds like a good possibility to look into.