rough idling '98 Prelude

I need help diagnosing the rough idle of a 2.2L VTEC. I have the
factory manual. I have replaced the plugs, distributer cap and rotor,
and plug wires. I removed the EGR valve and cleaned it with carburetor
cleaner as per the manual. The two codes which are still outstanding
are "number 4 cylinder mis-fire" and #1399, which is "manufacturer
control ignition system or misfire". I listened to the injectors with a
stethoscope (according to the manual) and all sound the same. Any help
would be greatly appreciated.

 

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).