'02 I35 Troubles

[ncm804]

Okay, I bought the car used almost a year and a half ago.
Earlier this year I noticed the car started running progressively rougher. Then the car started randomly turning off, first while idling, later more sporadically. Also it began slipping pretty bad. It now randomly slips or dies. I had the codes ran and I got a bad cam sensor, bad 02 sensor, and random cylinder misfire. I decided to change the spark plugs and found the back three ignition coils to be corroded, and one of the spark plug holes full of oil. The coil for the cylinder with oil in it actually broke into pieces when I was removing it. Now i've done some research and I suspect the valve cover. What I noticed when replacing the spark plugs, is that when I replaced the plugs I could drop the plug and it would fit snugly in the hole. The one that had oil in it though seemed to rattle around unlike the others though. Is that a result of the valve cover, or is there something more serious going on?
Also I would like insight into what can cause the camshaft sensor code to go off, and when I can to do check the sensors. Thanks in advance.

[maxhopper]

You need to replace the valve cover gasket ASAP or you're just going to mess up the new plug/coil in that cylinder.

No the plug should not have any movement once tightened down.

The easiest thing to do with the cam sensor is check the wiring. If the wiring is ok, replace the sensor.

[ncm804]

Do you think it's just the gasket or the whole valve cover? I'm planning on doing this myself so what are some other things to check for while I have the car dismantled? What things could cause the random dying/slipping?

[maxhopper]

Should just need to replace the gasket unless the cover is deformed. The gasket kit should include o-rings that go around the spark plug holes.

My guess is that the cam sensor issue is causing the dying concern. I'd get that addressed and see if that has any affect on the slipping. If not then you may have a seperate transmission issue.

About the only thing I would look for while you have the top of the engine disassembeld, would be to check for any sludge in the cylinder head, and clean the carbon out of the intake manifold while it's off. These motors are very solid, so there really isn't much to concern yourself with.

Here is a link to the FSM for your car. Info about the cam sensor should be in section EC. Engine info can be found in section EM. http://www.nicoclub.com/FSM/i35/2002/
(if you have problems accessing any info in there, go to the parent directory and look at the one for the 2002 Maxima, since all the mechicals are the same.)

[ncm804]

Thanks for the quick reply. I was just wondering if it could be the entire valve cover since the whole top of the motor was really greasy.

[ncm804]

Also when I had the codes ran, it didn't say which cam shaft sensor was messed up. Is there a way to tell, or should I just replace both?

[maxhopper]

The code should tell you which sensor is bad. P0340 is the one for the head nearest the fire wall. P0345 is for the head closest to the radiator.