For the last year and change, i've had misfires on 1, 3, and 5. I'm approaching 167,000 miles so today I picked up a pair of upstream NTK sensors. Am I correct to assume that being a whole bank, it's likely an O2 sensor? I wouldn't expect it to be anything in the valvetrain, but I suppose I should pull that VC off and take a lookieloo since I run the harland 1.7 rockers. Should I try replacing both driver side sensors instead of both upstreams?

 

The downstream O2 is used to test the catalyst efficiency.

That is odd, just bank one misfiring. Try the upstream O2 first.

 

That's what I thought. Upstream checks the A/F and misfire condition right?

If it was both banks, I would blame the MSD or Sean's tune or a sloppy timing chain or lifters or any of the other 500 worn out parts at 170K miles. But being one bank is really odd. So I thought, let's try the very possibly OEM/factory O2 sensors.

 

Do you still have the pre-cats on? Maybe bank 1 has failed, but it should trip the efficiency code.

 

Yea I haven't changed the precats. Being an 01 I don't have the option to just zip tie the down streams to the open air and do a cat delete.

 

well, might have found half the problem. Look closely at the blue wire of the old O2. Not only was the loom burned off, but the insulation was melted off the wire, all of which was laying on the catalytic convertor itself. No idea how that didn't throw a code.

O'Reilly's also sold me the wrong replacement O2's. The connectors dont match where the notches line up on the side.

20141221_113208.jpg

20141221_113247.jpg

 

I see the connector is keyed wrong and it looks short also

 

yep. So i'm gonna go chew some poor sap a new one soon as dad gets home from the store.

Closeup on the old wires

20141221_114612.jpg

 

This is the sensor I got, NTK 23135. O'R and Advance both say it fits. Wierd.

http://www.oreillyauto.com/site/c/detail/NTK0/23135.oap

http://shop.advanceautoparts.com/p/n...lVehicle=false

Looks like the 23137 is the one I want, based on photos.

http://www.napaonline.com/Catalog/Ca...137_0295696309

 

And the plot thickens. O'R shows no nearby warehouses with the 137 O2. Calling around right now.