rough idling '98 Prelude

"will" wrote in news: snipped-for-privacy@g14g2000cwa.googlegroups.com:

Have you cleaned out the EGR passages in the head? It will do no good if the EGR valve can pass gas (excuse me), but not deliver it in correct quantity to the correct cylinders.

Have you cleared the codes to see if they come back?

Thanks for replying. I cleaned the head passages as well as I could with a small brush/rag. The valve had some carbon build-up, but was not stopped up. I don't know if it means anything, but the valve leaks carburetor cleaner past the seat in the closed position. I checked it's operation with a vacuum pump, and it operates with no leak-down. The first codes read were, "system too rich", "cyl. 4 mis-fire" and two codes for "EGR insufficient flow detected". Now the only two recurrrent codes are the two mentioned in the first post.

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Has it ever stalled while it's warming up, like at a stop sign? What does your owner's manual say about the frequency of valve adjustments, and what's your mileage? The (early) CR-v manual is off by 55,000 Km, so I wouldn't trust the Honda owner's manual anyway . . . I think you need a valve adjustment / or it's too late.

'Curly'

Thanks for your response. It has not stalled, and runs fine at any RPM above 900 (using the car's tach.). The service manual calls for valve adjustments every 30K miles. The car has 128K on it now. As this is my daughter's car, and she bought it used, I don't know if the valves have ever been adjusted. I'll check them tomorrow (engine cold).