2002 tahoe. No power from take off.

[79jasper]

You check for clogged cats by doing a vacuum test.

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[Rocket Man]

There’s lots of ways to check for clogged cats- the temperature check with an IR thermometer at the front and back of the converter, a vacuum test, a flow test, a back pressure test, loosening the head pipes in front of the cats, removing the upstream O2 sensors. Google it and you’ll find explanations on how to do all of these as well as plenty of Youtube videos. Or go to an exhaust shop because I guarantee you they have the equipment.

 

[Steve01984]

Hey guys just checking in. So on my way home yesterday engine light went out and all power feels restored. Is it possible that the original bad knock sensors. Made itrun so rich/lean theat it possibly clogged up cat. But after fixed. It cleared it self out. After driving. I do drive an hour too and an hour home. Im hoping it did anyways.

 

[Rocket Man]

It’s possible the catalyst inside the converter moved enough to open up the airflow. Sometimes if you drive long enough on a clogged cat it can burn through the restriction or spit it further down the exhaust or out the tip. You might just try tapping on the converters and listen for rattling indicating debris. Time will tell if you’re any closer to figuring it out. Hard to say.

 

[Steve01984]

Update. Power keeps coming and going. One min feels ok. Next take off its a dog. Knock sensor code has switched. From b1 to b2. But went out on its own