My 02 gauge has been erratic lately, and has been showing off the scale readings, more than 18:0 to 1 - under WOT.

At this point I'm pretty sure it is the sensor, which I'm going to try to clean or certainly replace.

Wanting to know if if that was anywhere near correct, like, am I about to melt the pistons, I did a WOT shutdown after about 4 seconds.

These are the plugs.

Any comments? By the sooty layers around the base ring, I'm thinking it's running rich? I wasn't expecting that, I assumed if anything it would be lean.

The first two photos are cylinder 4, the second cylinder 2. Unfortunately, the camera didn't focus on the top of the plug, but more the middle and my hand. At least I know for next time!

there is a racing company with excellent pics on this that has been posted here but I been racking my brain & I cannot remember it. You might Google it. Here's a BTT

Wallace Racing is a good one.......Joe

X2 yes it was wallace racing that I was thinking of

Awfully hard to read a used plug, try installing two new ones in #2 and in #7 and then make a WOT for 10+ seconds and shut it off clean and show us those plugs

Were those plugs "new" before the test? They look fat and I don't see the burn on the elbow of the strap. In 4 seconds were you in the top of 2nd? What rpm?

It’s pretty fat. You are nowhere near lean.

If these plugs weren't new and used only for the WOT blast, they won't tell you much of anything.

It looks like they have been in the engine for a while, mixture is a little rich, and looks like you are burning a little oil. I would have to feel the black soot around the ring of the plug to tell, sometimes I wipe it on a piece of white paper. dry black is rich soot, oil is a little wet, to the touch..
You can tell a lot or a little from reading the plugs, depending how you do the procedure. WOT clean cut off, on the dyno, or at the track tells you the most. And a fresh plug each run. I am a tight wad, when tuning, a lot of the times, I will just put in one plug new each pass, until I get close. From the heat mark on the strap, the timing is close, maybe could use a couple degrees more. If you are rich at idle, the soot will cover over the WOT marking, by the time you get back to the pits.

On my drag car, the plugs read a little rich, when the O2's are at 12.5, the plugs start to turn tan colored, when, I read 13 to 1, I guess it is the placement of the sensor in the collector. Nothing is 100%, I just look at how many tools to get it right. Of course the time slip is the final proof, of how it is running.

A cylinder misfire will read lean on the 02 meter.

Thanks for the info everyone.

This is a street car, and the plugs have been in a while. With the 02 meter reading so lean, I was mainly looking to see it is anywhere near correct, as that lean would obviously damage the engine.

Had it in 3rd gear to make sure I wasn't spinning the tires, and only went for about 4 seconds, because if it WAS that lean...

Didn't see RPM, was too busy shutting it off and making sure I didn't hit the lock position.

It needs a new set of plugs anyway, so a better test is in order here. That and cleaning/replacing the 02 sensor.

New plugs,new test and shut off at the top of 2nd gear so rpm is above 5500 to get a fair reading for WOT.

the thin black timing line on top of the ground strap in the 3rd picture tell me the timing and possibly the jetting is not close to perfect yet, keep tuning
What plug heat range and compression ratio are you using in the motor now?

10.25:1, aluminum heads.

NGK BP6ES plugs.

Dyno showed most power at 32 degrees, so I have always kept I there. Will start to fiddle with that, it does have a good 5k miles on it, probably more.