1998 Honda Civic Strange idle

JOSHUA343

MEMBER
1998 HONDA CIVIC
4 CYL
FWD
AUTOMATIC
135,000 MILES

I have a 1998 Honda Civic Lx and it runs fine while cold but after that it barely idles. I went to check the idle setting and unhooked the connector from the idle control valve and the idle went up to almost 1200. When hooked up it barely runs witha hot engine. What do I need to look at next?

3 Replies

KHLOW2008

MECHANIC
41,814 POSTS

Hi joshua343,

Thank you for the donation.

When you unplug the IAC connector, the idling rpm would go up 1200 to 1400 as the valve is returned to the preset fail safe condition.

The low idling speed is due to insufficient air getting into the intake manifold. You can increase the idling speed by turning the idle adjust screw anticlockwise, adjust 1/4 turn at a time and wait for idling speed to stabilise before turning screw again. If it is not stable, clean the throttle body and IAC valve and readjust the idling speed.

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Wednesday, February 4th, 2009 AT 7:21 AM

JOSHUA343

MEMBER
2 POSTS

My throttle body does not look like the one in the picture. The air cleaner is square and sits directly ontop

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Thursday, February 5th, 2009 AT 5:34 AM

KHLOW2008

MECHANIC
41,814 POSTS

Ok, yours is another model throttle body but the idle adjust screw is similar, just that you need to remove the air cleaner assy to get at it. There might be a rubber plug covering it.

Cleaning process would be similar as described above.

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Thursday, February 5th, 2009 AT 6:17 AM