New catalytic converter?

[Stinky]

In 77Charger's situation... that will kill a cat...really rich mixture

 

[Bobalos]

In 77Charger's situation... that will kill a cat...really rich mixture

"back in the day"........... I saw more than my fair share of cats that were glowing red hot.  next up was a solid chunk of honeycomb that blocked flow until the motor could not breath any more. 

 

[Cookie]

I’ve had a bad engine coolant temp sensor give me hell in my buggy. Made it hard to start  once started it was very rich  I tested it it appears to be on the cold side and stuck there so was telling the ecu to add more fuel 

in your case a bad cat or o2 sensor should not make the car barely run. 

I believe, most cars have two 02 sensors on the exhaust, one before the cat and the other after the cat, all they are measuring is the difference between the two.  If they are the same, it tells you to replace the cat.  

 

[Don Parscale]

I put in Lucas injection cleaner in at every gas up, it makes a big difference. Buy it by the gallon and fill up the little bottles to keep in your vehicle. DON~~~

 

[endobear]

"back in the day"........... I saw more than my fair share of cats that were glowing red hot.  next up was a solid chunk of honeycomb that blocked flow until the motor could not breath any more. 

This just happened to the wife's Acadia. Cat came apart and plugged the muffler.