I too am being plagued by misfire CEL codes. I've read all the posts about misfire codes that i could find, and most seem to be happening while they're driving or after the car is warmed up. The problem i'm having is during warmup, more specifically when the idle drops from 2000rpm down to 1500rpms.

The first CEL i got was cylinder #1 & #4, second was cylinder #1 & #2, then it went to a consistant cylinder #2. So far i've switched coil packs, spark plugs, and listened to the fuel injectors. The injectors all sounded the same but i still ran some fuel injector cleaner just to be on the safe side.

A couple people i've talked to seem to believe i'm getting the CEL because of the fuel mixture changing during warmup and less back pressure from the exhaust (Invidia w/o silencers) contributing. I'm not buying into that due to the exhaust has been on the car for the last 20,000 miles, wouldn't it have caused a problem sooner?

Anyway, i'm trying to check everything i can before i take it to a dealership because i don't trust none of the honda dealerships that are in my area.

 

The Invidia isn't causing it. If it where, there would be a huge # of Invidia owners bitching.

Sounds like a leakdown test and valve clearance inspection is in order for #2.

Ever miss a shift and over-rev it?

 

change out your plugs and try some fuel injector cleaner, if that doesnt work then change your coil packs around.. if you had a bent valve your car would sound really rough.

 

A full compresion and leak down test is next on my list. I'm trying to get it tested this week, before the weekend hopefully. I've missed 3rd gear a few times over the past year but each time i was just cruising and the rpms never went over 8000 and i've never miss shifted to a lower gear. I ordered the car and picked it up at the dealership with 17miles on the odometer, every mile since then i've either been driving or riding in it. So unless it got a rough joy ride before i got it, i don't believe it has any overrev damage but i'm not ruling anything out at this point. I think i've read on here about some people having their valves needing adjusted as early as 30,000 miles and mines just over 30,000. Is there any tell tale signs they may need adjusted prior to pulling the valve cover off?

So far i've followed the troubleshooting steps out of the service manual and i'm at the steps now to start checking voltage and continuity at certain connectors. Which if they all check out ok, it says to do the leakdown test then switch out with a known good ECM. Thats where my investigating will probably end unless i can find someone who will let me use thier 03my ECM.

Otherwise the car starts,runs, and drives smooth as glass. I've even stood outside the drivers side with the hood up so i could hear the engine, exhaust, and watch the dash during the entire warmup cycle. The CEL light coming on is the only indication that somethings wrong. I'm open to any suggestions or ideas at this point cause it's got me stumped.

 

Depending on mileage and how hard you drive your car, most likely you just need a valve adjustment. When you do this, you'll now if you have bent valves, or other problems in the area such with the retainers or the valve springs.