Changed the spark plugs today but now got a question
 

So I decided to change my spark plugs today at 51,000 miles with the help of a friend and a DIY posted by javyLSU. It took 3 hours since my $0.99 spark plug socket wasn't working right and had my friend bring his over. Took a lot of time but at least I saved $280 not going to the dealer. They wanted $350 and I found the spark plugs on Sewell Parts for $13 each. Now my question is, when I took out my plugs, I think it was the last one from the driver side that has oil on it. The wire harness at the end of the engine where the plug was at also had oil on it. Is it bad to have oil on spark plugs?

I know I'm changing them 9,000 miles ahead of time but I'm trying to find out what's up with my car only getting 14-16 MPG. My tires are inflated properly, it has new Valvoline SynPower Oil, new air filter, I used BG 44K and Chevron Techron Fuel System Cleaners, and switched to "better" gas like how my dealer recommended using Shell V-Power or BP. Now I got the plugs changed and a new aFe Intake is next :). Here's now the plugs looked at 51,000 miles taken from my iPhone camera, actually pretty bad in person.

http://img828.imageshack.us/img828/5329/img0079bg.jpg

How is the car running compared to what it was before?

From what I understood, having oil come out near the end can foul your plugs. It's not getting a clean spark. It's been a long time and I may be wrong but that second plug looks a little fouled at the top. I'm seeing residue.

I'm not familiar with the back side of the valve cover on the IS since I've never removed it, but on my Civic there were rubber seals on the inside of it. Maybe the oil is getting through there. Maybe the Lexus mechanics can chime in.

Surprising, I noticed no difference with acceleration or anything. Until today, when I went to check my current MPG, I'm getting 23.4 MPG now compared to the 13.7 MPG I was getting last week using the same gas with the old plugs.

So it looks like my fuel economy almost doubled with new plugs! :woot:

I kept telling ya 13.something is no where near normal for an IS350 :p

Judging by those pictures, I don't see anything worrisome about your plugs. Have you checked the gap on them after you pulled them out?

Just curious: The crusty stuff on pic 2 is not corrosion? (Maybe I'm just too OCD...) :p
And aren't most plugs pregapped now? When I change my plugs I haven't had to gap them since.....geeze....since...um......... I was first driving back in the day. But I haven't had to change any in the IS at all so I could be wrong.

I noticed my MPG is dropping a little bit as well. I used to have 32MPG on highway. But now, I only have 28MPG. Mine is still 53k, I will consider changing mine at 58k at least. Good call!

Hmmm. Looks like I'm sorta wrong but not really - the residue is not good ...check out this article:

http://www.shouldpay.co.uk/how-to-ch...ark-plugs.html

On the bottom there's pictures for reference. :)