Idle speed, max RPM issue


So I have an 01 civic lx that has become my first project car, and it’s been working great for the last few months since I bought it. The other day as I was coming off the highway, she started a weird low pitched idle and the rpms dropped off. As I gassed it, the whole engine was slow to move and the rpms wouldn’t go above 4.5k so speed was out of the question since she’s a manual. Anyhow, wondering if anyone has any ideas?

Is the check engine light on? Have you read the codes? What are they?

What modifications, of any, have been done to your project car?

What engine is in the car?

Answer these questions and we’ll go from there.

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The idle air control valve may be dirty/defective,

Try removing it, and clean it with throttle body cleaner along with the throttle body.

If that doesn’t work it may require replacement.


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Since you apparently had your foot in it while not having any go I might theorize on several possibilities and it’s related to the fuel pump.

Either the pump could be failing or the electrical that powers the pump. That would mean the main relay or ignition switch. Hondas of this era are under a Recall for a faulty ignition switch which can cause a no start or stalling situation. If that Recall has never been performed then you can have it done free of charge at any Honda dealer.