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My name is mike , I did a tune up on my 07 equinox about 4 years ago . I didn't put a lot of mileage on it maybe 30 k . Anyway I decided to get new plugs and ignition wires . I took out the front ones first , cylinders 2 , 4 , 6 . Those plugs were worn out as I thought .Then I pulled the back plugs cylinders 1 , 3 , 5 , . They looked brand new .I have never see anything like this before . No dtc no hard starting not ruff idle nothing , It all seemed good . It looks like 1, 3, 5, weren't being used . It's weird to me , has anyone come across this before ? All input and help is appreciated . Thanks in advance .
Hey mikek! Would it be possible for you to post pictures of the plugs you removed?
In my experience, what you're describing is typical of a waste spark system (which your 3.4L engine uses). Three of the plugs are fired with a 'positive' polarity, while the other three are 'negative'. In other words, half the plugs have the spark jump from the center electrode to the ground electrode, and the other half in the opposite direction.
That results in three spark plugs that show wear on the positive electrode, and the other three that show wear on the negative. Thus, it might initially appear that three plugs had no wear, but they actually were. :silly: Make sense?
