KITT

Hey everyone,
When is it time to replace your 02 sensor?
My car has a slight rough idle still after I replaced all the injectors with brand new Nissan ones. I also had the exhuast manafold studs replaced. But there is still a very slight rough idle. You can't feel it when it is in drive at idle say at a set of lights but as soon as you put it into neutral it starts that idle roughness! I only use preium high octane fuel (Vortex Gold 98 RON from Caltex). It still has the original spark plug leads. Do these need changing? Or is the 02 sensor bad? Other than that the car runs great and is smooth while driving. Great fuel econonmy too. Only other thing that needs to get done is A Tranny Flush! $$$$
Any help would be great! Cheers

MadMaxBrent

If you fuel consumption is OK I wouldn't think it was the O2 sensor. It could be your PCV valve, gunged up throttle body or perhaps dodgy engine mounts. There are lots of other possibilities but these are the obvious ones to check first.

Brent.

KITT

What is the PVC valve? What is this used for? Is it cheaps to replace? How long do spark plug leads usally last? Mine are the original ones. I checked my engine mounts and they look fine. Injectors are new and I only run premium fuel in my max. What could be causing this slighly rough idle? Sometimes it is not there but most of the time it is, usally more when the car warms up to operating temp. Strange!! Any help would be great!

brubenstein

You put a scope on the output of the sensor and look at the wave form. Slightly rough idle is not the O2 sensor. Start with the TB and intake first.

If you want it to run like new, you have to make it like new.

eric93SE

iTrader: (1)

You should check all your vacuum hoses for leaks/cracks or loose fitting hoses. Hesitation at idle is usually caused by vacuum leaks.

I wanted to know what increase in MPG did you experience after changing all the injectors?

I just recently replaced my 02 sensor and experienced a %10 increase in MPG. My ride now has 73k on it. but I still get crappy economy 22MPG mixed driving.

PCV = Positive Crankcase Ventilation. I dont know were its locacted on the vg motor. I replaced mine also not too long ago but the original seemed to be in good working order. Usually the PCV cleans itself when driving high speed but they can get stuck from the oil residue and also they are very cheap (less than $5).

MadMaxBrent

Standing from the front of the car, on your rear bank (closest to firewall) on the RHS. It has a rubber hose feeding from the rear crankcase to the intake manifold. It screws in. Take it out and give it a shake. If you can hear it rattling it is probably OK.

Brent.