What are the symptoms of them going bad?

 

Thats a very broad question. Take one out and take a look at it. It only takes about 5 mintues for the front ones. Make sure they're relatively clean, no oil or whitish residue... as long as the electrode is all intact and not burned off its good. Any good do it yourself manual has pictures of bad vs. good spark plugs. Stock Nissan Platinum plugs are supposed to be changed every 60K... I have coppers which are to be changed every 30K... but they're so cheap its worth it.

Bad plugs can cause anything from hesitation to bad gas mileage.

 

Could it make your car start bad and make RPM's very active? What I mean is that it goes up and drops down really fast.

 

I highly doubt it.. sounds more like coil packs or a maybe even the crank sensor. I dont want to give you bad information but obviously I cant see your car. It sounds more like an electrical issue... I would say coil packs.

 

Well, i got two codes, one is for knocking sensor, and the other one is for EVAP canister vent control valve closed. But those don't mess up what I have.

 

Dont know brotha... I'm not a full fledged mechanic, I just work on my car on weekends. However, I do know about the knock sensor... change it. Its most likely running on safe mode and retarding the timing... so that may be partially the problem. The emissions system I'm pretty clueless about......

I say... go to a mechanic with experience...

 

Thats the whole problem, i went to a couple of mechanics and they are dumb as ****. Can't find any good ones.
But thanx for ur suggestions.

 

hey ant,

where's the best place to buy coppers?

Do you buy online or do you get someone like autozone/advance to order them for you?

pm me if possible. Thanks!

 

Hey, trust me I've gone through this problem, change the knock sensor. Ive just changed all the sparks, I used platinums, but I have the same problem. They say it's knock sensor.

 

you should change that knock sensor no matter what dude I change mine and it made a world of differance. I have heard of people losing 20-30 wheel horses because of a bad knock sensor. true or not I dont know but I know that mine ran 100% better when I changed mine

 

K.S. makes a world of difference.

 

Thanks guys, i will change it. How much would it run me with labor?
But i'm still trying to find out what is the problem besides that.

Anybody has a clue avout EVAP canister vent control valve?

 

fuel vapors are transfered from the gas tank,throttle body, and manifold to a canister with a charcoal filter when the car is not running.When you start the engine the vapors are purged from the canister via a purge control valve back into the intake manifold where they are burned up.Check the canister 1st for cracked or broken vacuum lines to or from the canister.It's located on the left side of the car behind the gas tank.If you smell gas fumes check for a cranked canister.Last the pmc controls the purge control valve so check the wiring for breaks or bare wires.From my experience whenever you have problems with rpm's fluxuating the first place to look is the vacuum lines but then again my wife's car threw a code for the purge control canister on her camary and it was because the gas cap was not on tight enough so with computerized cars it's hard to track down some of the simplist problems sometimes.Good luck!

 

I believe your EVAP canister vent control valve closed code is trying to tell you that the valve is stuck in the closed position...

See this thread on the usenet maxima group (long URL):

http://groups.google.com/groups?hl=e....com&frame=off