BDTMTGT

I've got a 2002 1.7L civic that starting throwing codes 300 to 304 for multiple misfires. It would come and go. Then one day driving home from work it started running rough, no code. I determined that I had a bad coil by disconnecting the coils individually till there was there was no change. Then switched the coil positions and had the miss follow the coil.

Installed a new coil and it started and ran a bit rough initially but then cleared up. Shortly after I got a 336 and 420 code. I started to believe that I'd toasted the cat because I'd driven it with a misfire(almost 100kms).

I reset the module, and the vehicle seemed fine again, for a while, then I started to get the 336 and the 300 to 304 codes. This time the vehicle shuts off and sometimes won't restart unless you let it sit for a while.

So far from what I have found in different forums and here is that it could be the cat, or that it could be the crank sensor.

Is there a way to test either of these?

Thanks

nsrhonda89

Check these links out.

https://www.civicforums.com/forums/3...d-bucking.html

https://www.civicforums.com/forums/3...-manifold.html

BDTMTGT

Problem Solved, I hope!!

I replaced the crank sensor, hoping it would resolve my issues. But unfortunately it changed nothing.

Then we took the cat off and cut it open and removed the honeycomb and packing(not sure what else to call it). Then welded it back together.
Still no change, thou we know that the cat is not blocked anymore.(still getting the codes thou for the sensors now cause its basically a straight pipe)

Then someone told my son(who owns the car) to try the simple things first, and try putting in some injector cleaner and some gas line anti-freeze.

Fixed!!!!! Water in the gas I guess, never figured it would create that much havoc!!!

BDTMTGT

Hey nsrhonda89, my problem came back. Its random, but always gives multiply misfires. The check engine light will flash, at times but goes solid above 2500rpm?

Thought about the video you posted. The 2002 doesn't have an EGR valve, but does it still have those ports and areas that could still be blocked?

Thanks