Flat Spots At Certian Rpm In Manual Mode On Auto + Alot Of Black Smoke/ruff Idle On Start Up

[blaek]

Hi GUys,

Its probably a ditry AFM or plugs or o2 sensor, but best for you professionals to determine

Past couple of weeks noticing random flat spots through the rev range, still have power, just rpm sits for abit before climbing again.

Just started the car, drove it this morning with no worries, very ruff idle, black smoke starts belowing out. stopped the car and started again, perfectly fine, no ruff idle, no smoke. No mechanical noises can be heard ie knocks etc

any ideas?

[KiwiRS4T]

Get some new copper plugs (you don't say what kind of Stagea you have) and give the coils a good clean and examination while you're at it. If its a C34 get a new O2 sensor from Kudos

http://www.kudosmotorsports.com/catalog/ngkntk-sensor-lambda-oxygen-nissan-rb20det-rb25det-p-42.html

[zei20l]

if its an M35 dont use copper plugs, its a PITA changing them

[Stagea Gazza]

I recently noticed that my fuel economy is not as good as it used to be. This was starting to hurt on 98.

Firstly I cleaned/re-oiled the aftermarket k&n air filter (yes it was filthy) and cleaned the air flow meter with mass air flow sensor cleaner.

I have today received a set of spark plugs for the M35 - there is a bit already written on this topic and I chose the NGK Iridium IX (LFR6AIX-11) from PerformanceLub.

Just to cover everything I picked-up today an o2 sensor from Nissan. For the M35 this is 22690-AQ800 at around $160 incl GST. Not cheap but neither is fuel...

Sometime next week I will get around to fitting the spark plugs and o2 sensor. I will also try and get the injectors cleaned off-car.