My 5th gen is misfiring and throwing the MIL. I took it into the dealer about 6 months ago after the MIL came on and they just read the code, reset it, and told me it was fine and that I should drive it harder (B.S.).

A couple weeks later I took it to another shop and they did a full tune-up, replaced the plugs, cleaned the injectors, and replaced the fuel filter (the mechanic said things were pretty gunked up, and that if it starts running poorly again, that the injectors might need to be replaced). A couple days later, it's running bad again and I buy some new injectors and replace them myself. It ran great for the first two times I took it out, and it's misfiring again and throwing the MIL.

Any ideas??? I'm not exactly the experienced car tech, and I don't know where to begin.

 

maybe clogged egr valve?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrettyLude &raquo;</TD></TR><TR><TD CLASS="quote">maybe clogged egr valve?</TD></TR></TABLE>

Not the valve but.. possibly the egr ports in the manifold

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lodie &raquo;</TD></TR><TR><TD CLASS="quote">My 5th gen is misfiring and throwing the MIL. I took it into the dealer about 6 months ago after the MIL came on and they just read the code, reset it, and told me it was fine and that I should drive it harder (B.S.).

A couple weeks later I took it to another shop and they did a full tune-up, replaced the plugs, cleaned the injectors, and replaced the fuel filter (the mechanic said things were pretty gunked up, and that if it starts running poorly again, that the injectors might need to be replaced). A couple days later, it's running bad again and I buy some new injectors and replace them myself. It ran great for the first two times I took it out, and it's misfiring again and throwing the MIL.

Any ideas??? I'm not exactly the experienced car tech, and I don't know where to begin. </TD></TR></TABLE>
What he meant by drive it harder was to remove any deposits from the injectors that may be preventing fuel delivery. Misfires are usually caused by fuel, spark, and/or compression. If fuel and spark aren't your problem there may be an air leak. Best thing to do is to do a compression, and if compression is bad a leakdown test to find out where the air is escaping to. Hopefully this helps. Oh year where are the misfires, is it in just one cylinder or more than one?

 

On the writeup that the dealer gave me, they said that if the problem persists, that the next thing they'll check is the EGR valve. When you say that it would be the ports in the manifold, is that something that can be as easily reached as the EGR valve itself? I was planning on taking it off and cleaning it out. Is carb cleaner appropriate?

I am going to get the latest codes that have been stored to see if it's a single piston not firing, but I was under the impression that it wasn't particular to just one.

I agree there's some truth to the "driving it harder" comment and removing deposits that have built up, but I felt like I was driving it plenty hard as it is (hitting the VTEC a couple times a week).