TheRadiantMini

I have a 2000 honda civic ex and it was fine one minute and later on in the day it idled rough and the whole car shakes. The exhaust does not sound the same almost sounds like a motorcycle exhaust. The check engine light is also flashing. I took the car to autozone and they told me I had multiple misfires on all 4 cylinders. code P0300 The car just had a tune up last year. Any ideas? My buddy said something about a button cap and rotor? I've also heard it might be the heated oxygen sensor. Any ideas?? I'm not super car savy (just a geek) And if there are any DIY guides I can usually handle that. Thanks a much!

02civicsi02

Multiple missfires can be a couple of things. And your buddy that said check the rotor or button cap he is referring to the rotor in the distributor. You might need to check that it could be corroded. Just take off the distributor cap and look at the rotor attached to the distributor housing. Also check the inside of the cap on the metal prongs and see if they are corroded as well. You might need to check the spark plugs also. They could have went bad. I dont think the primary 02 sensor would make missfires. The primary 02 sensor is the air fuel sensor. It just measures the air flow mixture and would only make the car run rough and idle different.

Another possible thing is your timing. If the timing is bad or jumped teeth it can cause multiple misfires in a couple of cylinders or all of them.

TheRadiantMini

Ok I will check all that out and get back with you. thanks!

TheRadiantMini

Went ahead and threw on a new cap n rotor but that didnt fix the issue (Should i put the old one back on and return the new one?). We did a tune up on the car 2 years ago (plugs, wires, cap rotor). The timing belt has never been changed though (to my knowlege). Car has like 125k miles on it. Any other ideas? This is my girlfriends car. Thanks

TheRadiantMini

I forgot to add that I can definately smell the hint of gas while the engine is running.