Rep Power: 0

Okay I'm new here and can't figure out what is going on with my car. I have a 2002 Civic EX. At about 8K miles I installed a AEM true cold air intake with bypass valve and also installed a Tanabe catback exhaust system. Things were going well then about 3 months go buy and one morning I start up my car and I get an engine light. So I do what everybody hates doing I take it to the Honda Dealer. (It is still under warranty) They read the code and it says that #2 AND #3 cylinder misfire. Well they reset the light and it doesn't come back. Well about 4 months later (a few weeks ago) the same thing happens. Take it to the dealer, dealer resets light, no light for a week. Light comes back on take it to dealer, reset light, comes back on two days later. Every time it is #2 and #3 cylinder misfire!!!!!!!!! The dealer is gonna fix it. They have it right now and will have it for the next week or so. Now here is the QUESTION? What would cause this?? The dealer did swap coils on 2 and 3. This changed nothing. Plugs have been looked at and are good. Compression test is good. I've been told that it could be bent exhaust valves. And I have been told that because of my exhuast with the 3" pipe and no turbo it causes low back pressure and can bend valves. Is this true???? Sounds kinda funny to me but figured I'd ask the guys that would know. Help me out I don't wan't this problem to come back after the dealer gets done with it. Thanks

 
Rep Power: 811

i'm having some idle problems with my exhaust on startup that i'm trying to figure out. but 3" inch pipe is pretty big. still, there is no way you can bend valves by adding intake and exhaust. thats rediculous.

 
Rep Power: 0

didn't think it was possible just waiting to see what the dealer says. I'm not sure what kinda idle issues you have but i really have no idle issues and really nothing else going on. It's hard to start in the cold and the light somes on about every other day but I never notice a misfire. All this happens only on startup never while I'm driving down the road. Thanks for the info though. Should I go to a smaller pipe atleast till I get my turbo?

 
Rep Power: 811

you could always try to find a silencer on ebay and put that on to restrict airflow. it will acomplish the same thing as smaller exhaust.

 
Rep Power: 0

yea i have the same problem.....i have a 98 ...ex....2.5 inch exhaust....engine light comes on...aftermarket cat ...i think its an O2 sensor...cause i'll pull it out...and it will be black...i think its old...

 
Rep Power: 318

An after market cat can cause problems with an OBDII car, that is possible. You can get an O2 simlator (sp?) to correct the problem, but be warned that it is illegal to run with that, not that I've seen cops ever check for it.

As for your exhuast being to big, that's BS. I've ran cars that where open after the cat for month and never had problems with misfire. The whole thing about needing back pressure is not worth that much power and certianly would cause that.