Misfiring and P0420

DodgeEvo · Post by **DodgeEvo** » Tue May 01, 2012 4:43 pm

Ok so when I go to take off or step on the gas at any time my car seems like its misfiring and then I hear a knocking sound. I think it might be one of my coils, not to sure. Code P0420 has shown up.

Caraudioholic24 · Post by **Caraudioholic24** » Thu May 03, 2012 8:33 am

It may be a bad cat or O2 sensor...

I would first check the wiring that goes to the sensor since they like to melt/wear out after a while if its in a bad spot. Hope you get it fixed

Post by **occasional demons** » Thu May 03, 2012 9:21 am

The misfire may have burn't the cat out from overheating it, but you should have had a code/CEL for being too rich before that happened.

I can't see any other relationship between an cat not working and poor engine performance. Unless the cat brick is the knocking sound you are hearing.

DodgeEvo · Post by **DodgeEvo** » Thu May 03, 2012 5:29 pm

Well the light is out and the car is running excellent, better than before. My thought is with my new hood, maybe some water got in and hit were the coils were. Not sure, but still looking over things.