• Tiny
  • paul64
  • 2001 Mitsubishi Galant
  • 4 CYL
  • FWD
  • automatic
  • 110,000 miles

I suspect my catalytic converter is going bad. I do have some of the symptoms of it being bad, ie gas mileage is not so great anymore, a slight vibration and I can see the exaust pipe actually slightly shake. Not always but sometimes I do get the foul order of rotten eggs but not always and the overall engine performance is not optimal. Sometime last year I replaced bank 1 O2 sensor, a few months after that I got a CEL with a p0420 error code and I ended up clearing it to see if it would reappear again but it never did. A few months after that I had an error code for cylinder 2 malfunction and ended up replacing an ignition coil. My question is, is it safe to say that the possible cause of a bad cat converter was a bad ignition coil failing or could there be something else causing it. The check engine light has not turned on and not sure where to go from here. It has already been almost 4 months since I replaced the ignition coil. Please help

Do you
have the same problem?
Monday, June 13th, 2011 AT 12:45 AM

1 Reply

  • Tiny
  • rasmataz
  • Member

Could be if the spark is weak on that cylinder and its not burning completely and producing high HC-unburned fuel thru the exhaust

Was this
Monday, June 13th, 2011 AT 12:55 AM

Please login or register to post a reply.

Similar Questions