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New member, hopefully I'm posting this in the right spot.

I've looked at a number of other idle issues here, and although in some cases similar, not exactly what I'm experiencing. Before I launch into the IACV and removing the throttle body, I was hoping to get some opinions.

I have a high mileage (330k), completely stock 2000 Civic EX that I've owned since it was new. I've always replaced plugs with NGK from the dealer.

On Friday night with my wife driving, the check engine light came on. Idle became poor. I had a chance to look at it yesterday and this morning. Codes 302, 303, 300, and 1399 were thrown. I checked all the plugs, since I got the cylinder misfire before owing to not tightening down the plugs well enough. Plugs 1 and 3 are perfectly white, 2 and 4 a little blackened, but still in good shape. I think I replaced them about 10k-15k miles ago. I called the Honda dealer and wanted some advice from the service dept, all they said was that I probably had a burnt valve and it wasn't worth troubleshooting. Bah, this car still has life in it.

I cleared the codes and fired it up - idle was very rough, it stumbled, and eventually settled in at about 1500. I drove it for a few miles, including on the freeway and it drove really well. When I parked it, idle was extremely low (< 500), but rock steady.

From appearances, the plug wires look ok, no obvious cracks. Based on what I've read, is my next step to take apart the IACV and clean it? Since it seems to be below the throttle body, I'll have to take the throttle body out. I'm assuming that I'll need to replace gaskets if I do so, and since this is my first time digging into the Civic other than routine maintenance, I want to make sure I'm not overlooking anything else. What specific gaskets should I have available when doing this work? I hate multiple trips to the store. :P

Thoughts?

Thanks very much!

-JP

 
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http://honda-tech.com/showthread.php?t=1575913

 
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Thanks, I was looking at that article. Would you believe my problem was mostly caused by a bad cap and rotor? This sounds stupid, but I play around with mostly older cars and I just kinda thought that the 2000 Civic didn't have a normal distributor. Joke's on me, huh? 335k miles and I've never changed the cap and rotor... They looked pretty bad.

But in rotating my engine to get to the screw on the rotor, I fried the ignition coil. (Make sure you ground the coil before cranking!!) $52 later, I had that problem fixed and it fired right up.

Engine put out an O2 low voltage code about half a mile down the street - great. I thought maybe all the gas I pushed into the manifold without firing caused a problem, so I cleared the code and it hasn't been back in over 100 miles. The engine still runs a little bit rough at idle, but not bad at all. If I feel adventurous, I'll order some new gaskets and clean the IACV next.

-JP

 
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Had the very same problem... Oh and watch out for the wires... I replaced my wires cap and roto on my 96 LX and I had them magically popiing off the spark plugs on occasion...

But, the low idle... Removing the throttle body is really nothing to it. I found 1 o-ring as hard as a rock in one of the sensors and the IACV was extremely gummed up. Basically stripped it down and soaked it in Marvel Mystery oil minus the sensors and replaced all gaskets.... Idles as smooth as can be now. Took me less than 20 minutes to remove the throttle body off the car.