I tuned my truck here a while back. HP Tuners, no wideband. Basic tune using O2 sensors. I pulled a couple plugs today just out of curiosity. Almost all of them are completely white. They're supposed to be tan-ish, right? Everything looks right in the tune and logs. Except, when cruising at highway speeds me O2 look like a heartbeat monitor. Jumps from as low as 100 to as high as 890's. Is that normal? I did change the MAF recently because the previous owner descreened mine. I used a MAF off a 4.8 or 5.3, can't remember. My motor is a 6.0. Is that a problem?

 

maf doesnt matter, they are all the same. the plugs will always look white. The engine runs at stoich (14.68) most of the time. for a plug to be brownish the engine needs to be in the 10-12 range.

 

As for the O2 voltage fluctuating between .1 and .9 volts, that is normal, the O2 voltages should fluctuate rapidly if they are functioning properly.

 

Did you mess with any of the ve or pe tables? Take a pic of the plugs.

 

ok thanks guys! I thought I might be running really lean. I have a big background in atv's, and plugs in atvs are white if you're really lean.

 

So do I, and white mean lean yes, but your truck runs at 14.68 98% of the time, the plugs will be white....


These are mine plugs with a tune that was pretty much spot on, with a/f in the low 11's
Plugs have about 400 miles on them.

 

Ok, great! Now I can stop worrying. Those look just like mine.

 

plugs are ok to be white, but i would be careful about tuning wot without a wideband, those nb 02's are not something to be trusted for that.

 

Good point, I kinda skipped over the fact of tune without a wide band is not a good idea...