Originally Posted By: PandaBear
Originally Posted By: ThirdeYe
The old ones looked white at the tips, which I believe is from running lean? One or two of the plugs were slightly out of spec, too. The gaps were too large on them. The plug closest to the passenger side is always an absolute dog to get out, no matter how gentle I put it in and I'm careful not to cross-thread. I have to turn with all of my might to get that plug out. The others all come out fine.
Is that hard to get out plug also one of the out of spec one? Sounds like mine when it had head gasket issue, except mine had a tint of green coolant. Post some pictures of the old plugs and run a compression test to see if you have head gasket issue.
I have huge concern with your head gasket if the plugs don't wear evenly. If it is not head gasket, that points to downstream from distributor to wires or the plugs. Adding the fact that it is hard to get out I believe you really have to check if your head gasket is fine.
If you want to save money borrow tools from autozone to test your own. I did that at work place parking lot with a coworker in 30 minutes. It is not hard and will give you a ball park idea of what is going on.
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Anyways, I took the car for a short drive and turned it off/on twice even with the AC on (for extra load) and it didn't give me any issues. I may not have driven it long enough to fully warm it up, however, so I'm not convinced that it's fixed.
Is it even possible for spark plugs to cause a problem like this, where it'll misfire at idle or under load when the car is warm or started after it's warmed up? My novice theory is that if the O2 sensor was bad, perhaps it fouled the plugs by having the car run lean, thus causing the misfires. -shrug- I wish I knew more about spark plugs.
I'm not really sure what a fouled plug looks like, so I'm just guessing.
O2 sensor shouldn't cause uneven spark plugs wear between cylinders. It could throw cell, cause fuel economy drop, make all plugs on the same bank (in V engine) go rich or all go lean, but not just one or two cylinders.
O2 sensor being bad should throw a cell, if you want to throw parts at it you can try junk yard or rockauto generic (NTK or Denso would be ideal). If you have high miles, probably due anyways.
The plugs all looked the same to my naked eye, but the gaps were a little different from plug to plug. Some were still in spec, some were not. Unfortunately the plug that was difficult to get out wouldn't make for a good picture because I had to soak the cylinder with PB Blaster to get it out. This got all over the plug and washed away any color that may have been on the plug. All of the plugs had a white-ish tint to them. I cannot remember if my plugs I replaced before these had that tint to them or not. I don't think they did. I may actually still have a pic of one of my previous sets of plugs after I changed them. I'll have to look and compare when I get home. I'll post a pic of the last set of plugs when I get a chance, too.
The plugs I'm using are pre-gapped by NGK but they aren't exactly the same, so I wonder if that caused a few to become out of spec after they wore down a bit. I noticed that with this new set of plugs they were all in spec but not exactly the same gap. My theory is that the plugs that were gapped the tightest remained in spec where the ones that may have been gapped closer to the outer spec may have gone out of spec after they wore? I'm not even sure if a faulty O2 sensor (which I truly do believe it was faulty) would cause plugs to wear prematurely... or if lean/rich conditions would wear out plugs.
I think it is possible that I have a head gasket issue, because I was told that coolant was leaking from the IACV... but I wonder if it could be coolant leaking out from the head gasket? I haven't seen any white smoke at all, or any sludge/milky substances in the oil or under the valve cover. The oil still looks pretty good.