ruff idle

[240sxracer]

it started about 3 days ago when the engine's cold it runs rough and misses pretty bad, but as soon as it warms up(about 5min later) the idle smooths out and it runs fine.
the plugs,wires, and f-filter are all new. can it be the oxygen sensor ive had the car for about a year and i have not replaced it, nor do i know how long its been on there. could this be my proublem.
thanks for any suggestions. what else could it be

[whateverjames]

check your ECU and see if it yells at you about your o2 sensor
<a href="http://240sx.org/faq/" target='_blank'>http://240sx.org/faq/</a>
scroll down to ECM, reading trouble codes

[camppain]

an o2 sensor is not a maintennce part like your plugs f filter and oil and oil filter why do people think doing this will clear a problem dont shutgun check your basics like your idle first your timing etc etc

[geeaj]

Idle issues check:

MAF
TPS
IAV

These could use a good cleaning.

The connectors could be lose or corroded. You should also check your vacuum hoses or the intake boot, sometimes cracks can develop and cause some of the problems you've described. If your ECU isn't throwing a code, chances are its not the O2 sensor. The FSM has a specific process for checking the o2 sensor if you want to do it.

[240sxracer]

i fully dismantled the aiv cleaned it(it was nasty) not sure what its called on the aiv,but its like a diaphram or something on the top of the aiv actually rusted out so i have to go to the dealer tomarrow to get the part so i can replace it.anyways since i cleaned it(earlier today) the proublem has been fixed.