kevykev1969

My daughters civic started out with a cylinder #2 misfire, I switched the coil with #1 cylinder and came back up with cylinder #2 misfire so I checked the plugs they didn't look bad #2 looked like it was running lean so I replaced #2 injector and went on ahead and replaced the plugs with NGK iridium plugs, it was o.k. for about three weeks and then it came back with multiple cylinder misfire between 45-65 mph under load. I pulled the plugs again it looks like cylinder #2 is running lean the rest of the plugs look fine, I did a compression check and the cylinders are all in range between 175-180 P.S.I. I've been doing some reading up on it and found a lot of multiple misfires are caused by the EGR passages being blocked with carbon build up, there is no low flow EGR code, I do not have a fitting to test the fuel pressure, I replaced the fuel pump 8 months ago with a new Honda fuel pump the old one was cracked and leaking on top. My question is could the blocked EGR passages be the problem even though there is no EGR code or should I look elsewhere? Any helpful answers is much appreciated.

ezone

Most of these engines will not set a low flow code.


Unplug the EGR valve and drive it for a few days. Check codes in a few days. The only code should be for EGR because it's unplugged.

If there are no misfire codes after driving in the usual manner where it normally would have set codes, then you can go ahead and pull the intake manifold to clean the EGR passages in the distribution plate and ports.

(If it still set misfire codes, then EGR is not the answer.)

You will find that the cylinder that was setting misfire codes is the only one that still has EGR flow, the rest will be almost completely clogged.

kevykev1969

Thank you Ezone, I'll unplug the EGR for a few days and see what happens, I'll post the results.

ezone

I should have said these will set misfire codes before setting a low flow code.


Good luck

kevykev1969

OK, Thanks

kevykev1969

I cleaned the EGR ports and distribution plate two weeks ago and haven't had any miss fires . Thank You for the help, and have a Merry Christmas and prosperous New Year.

OneJzSupra

I had an issue kind of like that, after replacing a lot of stuff I ended up changing the computer which fixed my issue.

kevykev1969

so far there has been no miss fire issues since I cleaned out the carbon build up, but it was only doing it we noticed when the temperature was hot outside, I'll have to wait until the weather warms up to know for sure if it's fixed. Thanks for the info OneJzSupra