I'm about to hit 105,000mi and I know this is tune up time. I want to be ready when the time comes. I have a question about the pcv valve whether or not to replace it. On my past cars (Hondas and acura) I replaced the pcv, but when I went to the dealership they said you dont have to replace them on infinti's. They parts guy said he sold 1 in the past 2 years. I know its a cheap part but I dont want to spend more than needed. Also, do you guys replace the radiator cap?

The PCV valve is a common failure item on our cars too. If it hasn't been replaced in 105k miles, I would replace it. It's cheap and can save you hassle down the road.

When I replaced mine after about 85k miles, the rubber O-ring on it (make sure you get this too, by the way) crumbled into dust when I took the PCV valve off...

Yeah the one I saw has the O ring too. Thanks.

The most important part of the tune up is replacing the spark plugs. Have you done it yet?

Nah, but I am.

Make sure to check for oil in you spark plug tubes.

Yea I was asked when I was getting plugs if I wanted to get a valve cover gasket. I might just get that too.

Well as for the oil in the spark plug tubes the whole valve cover has to be replaced unless you can have the down time to have them sent out to be rebuilt.

Index ur plugs. Pointing the gap of ur electrode towards the incoming fuel / injector allows for better atomic reaction (or more efficient burn). U can mark ur extension w a sharpie or grease pen and proceed to torque them as specified.

Yes I have it done in my car. No I didn't get a million HP but the response cooling n burn equalize a curve ur a/f monitors are already programmed to try n make happen.

And use a higher heat index when buying a replacement plug. Spark plugs allow heat to escape which is a good thing.

im at 105k miles myself and you will find that doing spark plugs is the tip of the ice berg.
the valve cover issue is the main problem.
you can change the spark plugs all day but if you get oil in them they aint worth a damn.

Figure out how to get those valve covers replaced.
Sometimes the places that change o rings include the pcv valve also (cause technically it is part of the valve cover when ordered, atleast from Nissan, )

Here's one palce that does them:
http://my350z.com/forum/engine/54492...-covers-5.html

Plugs, Oil/Filter, Diff Oil, Trans Flush or Drain, PCV, Intake Air Filter

I would also change the Rad Cap for piece of mind. A lot of people don't understand the importance of a radiator cap.

Also, I would drain and fill the Power Steering Fluid and Brake Fluid too. Check Brake Pads for wear, along with tires.

If you do all of this yourself you can save a chunk of money if you pay for these services it'll get hefty rather quickly.

Thanks for the info.

I replaced my spark plugs with OEM ones 2 days ago on my 06 sedan. Comparing the two, I'm surprised the car would start with the originals. It also explains why I was pretty much getting around 14MPG in the city and 20MPG on the highway. I didn't get around to changing the PCV valve, but I will purchase it soon. The car idles a bit more smoothly and power seems to come on smoother as well just with the plug replacement. If you're looking to do this yourself, there is a video on InfinitiHelp that shows you how to do this although there are some things he does to access the plugs that I didn't see the need to do. If you have some decent mechanical skills, you'll see when what I'm talking about when you start working on it yourself.

Did you have oil on the plugs? How much you pay for 6 plugs?

I had 111,xxx on the odometer when I changed the plugs but didn't see a drop of oil on them when they were pulled. I was worried that they would have oil on them since that problem seems to be common, but both sides were clean. As prevalent as the problem is, or as much as you read about on the forum, I'll go ahead and consider myself lucky. The only thing I did when changing the plugs was checking the gap and setting them to the recommended specs according to my manual.

I actually purchased my plugs on eBay from Beshoff Infiniti in San Jose, CA. Hopefully the links below work.

eBay OEM Plugs

Beshoff Infiniti eBay Store

Including shipping, all 6 OEM plugs came out to $54.40.