GenVibe - Community for Pontiac Vibe Enthusiasts

A bit of chronological history (See viewtopic.php?f=12&t=39166" onclick="window.open(this.href);return false; for more detail)

1. Car could barely go 50 miles per hour.
2. A mechanic looked at it and determined that the back pressure test was off the charts. Cut off the cat converter by the second O2 sensor. Looked OK--certainly nothing that would cause back pressure readings to jump off the charts.
3. Removed the front exhaust assembly and noticed the cat converter built into the exhaust manifold was at least 70% plugged.
4. Gutted the plugged cat (very simple procedure, by the way) and acceleration problem went away. Runs smooth and fairly quiet.
5. After approximately 100 miles of travel the DTC P0420 came on.

I'm in the process of establishing baseline MPG.

So, I would appreciate some suggestions: (Would giving you O2 sensor voltage readings help?)

Gutting the CAT is what is causing the CEL. Guessing it will continue to re-appear until the CAT is replaced. Some have had success "fooling" the sensors (search will give specifics). I opted to replace the cat rather than screwing around with the sensors etc.

Pat

DiveNut wrote:... opted to replace the cat rather than screwing around with the sensors etc.
Pat

I would opt for replacing the manifold/cat assembly. The $300 - $500 it would take is cost prohibitive right now.

If you're still working on this. Ad an 02 extender from ebay, or google spark plug anti fouler 02 extender. It will stop your CEL from coming back on.

Phew! Your title made me think you had disemboweled a cat at speed on the road. Good to know the facts now!

Just build your own O2 sim. You can find diagrams online and all the parts you need cost no more than $15. I ran for the longest time on a sim (Full Header = No Pre Cat =P) with 0 issues. All the spark fouler/extender methods will eventually pop a P0420 again. Just make sure you only sim the POST cat O2 since the pre cat O2 is your AFR reading

Is "gutting the cat" legal?