I know most people say that you will not notice any improvement at all when switching to high performance plugs but I must disagree with that. Today I removed my old plugs (plain Delco'*) with some NGK Iridium IX'* that I had sitting around for a couple of months and I was amazed at what a difference it made. I started her up and all went nicely, went for a cruise and I definitely noticed a slight boost in acceleration response which gave me a pretty nice smile. Man was I flying! I was sitting at a red light at one point when I noticed that my idle speeds and idle vibrations were much less than before. I am really happy with the result of these new plugs and it was the first time I ever installed spark plugs. Im having a problem though I think. The engine sounds just a little bit different, kind of like its dry on oil or maybe a very slight knock. I put in a quart of oil and it still sounds the same so Im assuming its because of the new plugs. I gapped the plugs to .055 on each one of them and I installed them according to my Haynes book although I didnt have a torque wrench and some of the plug holes had a bit of grime so I just tightened them all to a certain point. Ive heard talk about misfires but I have no idea what that is, could this be some sort of a misfire going on? Or maybe its just because they are a colder plug than the Delco'*. The Delco'* were gapped at around .062-.065 so I dont think I did anything wrong with the gapping of the NGK'*. Right now I dont really mind it but if its bad for the engine and can mess things up big time then I need to get this fixed and would appreciate any help you guys can offer.

Any new plug will feel better, especially if the old plugs were gapped over .060".

In all reality, you'd be hard pressed to notice a difference if you switched to a cheap generic champion plug right now. You re-gained lost performance, but you can't really feel the difference from one plug to the next in a straight-up comparison.

Yea youre right although the plugs that were in there were in excellent condition with just a slight bit of white "frost" on the curved thingy. Any ideas on the sound though? I didnt realize this thread was in the 92-99 forum, maybe it should be in Performance?

You put in a quart? Was it that low? If so, you have a serious problem.

Your old plugs were gapped wrong. I'd expect the motor to sound differently with the new plugs.

You're in the right forum. Plugs aren't really a performance item unless you're in extreme heat ranges.

Well when I changed the oil just over a week ago I put in 4 1/2 quarts and today I put in the rest of the 1/2 quart and put in 1/2 more from a new bottle so i guess you could say it now has a little too much oil. The oil wasnt low according to the dipstick but I thought maybe 4 1/2 quarts wasnt enough so I put more. Glad nothing is wrong, thanks Will. Got a big project Im starting tomorrow so I thought I would put the plugs in today.

Overfilling your oil can be very bad news on engine seals. Drain it back to the full line as soon as you can.

Another thing, just for future reference. If you're going to do your intake, wait until after the job is done and you've run the car for a few miles to put in new plugs. There could be traces of loose gunk or dirt that need to get through your system right after reassembly, and since you're going to need to change your oil soon after you do your intake you might as well wait until then to put in your new plugs. This is what I did with my recent LIM gasket change (of course, I ran a can of Seafoam through the motor as well), but you might as well keep those expensive plugs from getting any junk on them by running your system clean before installing them. Just my opinion, maybe I'm wrong. Do well tomorrow! Take pics of anything that you have questions about.

That sounds like you're a little lean. I think the rear plugs have a tendancy to do this more since they are so close to the exhuast manifold/downpipe.

I want to make this clear before I say this -- I am NOT insulting you.

If the oil is not low according to the dipstick, why did you overfill it? There'* never any reason to think that you're smarter than the engineers that built the car (well....only sometimes

How slight is this 'knock' you talk about?

Well the level was just at the bottom of the x'* so I figured "ah why not?" just to see if it fixed the slight noise problem. The noise isnt really something you notice if it was some stranger walking by but I guess its just different to me because the plugs are at a different gap and Im used to hearing the engine with the other plugs. It sounds a little bit meaner and the so called "knock" Im hearing is only during idle so I think im alright.