Sounds like I'll be making some calls tomorrow!

Forgot to mention that it threw a P0171 code on the way home.

And for the future - after replacing a cat or 02 sensor, what's the quickest/best way to drive the truck to get the sensors "ready" for emissions testing?

Thanks guys!

 

Annnd here's a good laugh for everyone today!

I went through all that trouble to wrap the O2 sensor in a ziploc bag, then in a few layers of industrial duck tape to make sure it was waterproof, and zip tied it way up underneath the truck to keep it out of the snow/salt/crap on the roads.

I just went to unwrap and re-install the sensor, only to find it had slipped out of the zip tie, and spent almost the whole ride dangling in front of the open sensor bung! Plastic bag, duck tape, glue - allllll melted to the O2 sensor! Maybe I'll get lucky and find out that sensor was the problem all along!

 

40 mile trip today to pick up some furniture - ran perfect the whole time.

Had the laptop hooked up to the truck monitoring the sensors - both O2 sensors bounced all over the place, the whole time, anywhere and everywhere from 0.1v to 1.2v, with no correlation between the two.

Any chance my problems could have been caused by two bad O2 sensors, and the Cat is still good? Or are the O2 sensors and Cat in this together, plotting against me?

 

front 02 should be bouncing back and forth on voltage if it's working right. Downstream 02 voltage won't vary to much,as it's not involved in air/fuel monitoring like the upstream one. Have a muffler shop measure backpressure before the cat. More than 2psi, it's shot.