car wont pass smog

[831_salinas240sx]

I have a 91 240sx HB, its running on a KA24DE w/ 5 speed transmission. and I live in California so every 2 years or so we have to smog our vehicles. so when i took mine in it didnt pass. the issue was called "foul pollutor" I believe its the air sensor that is causing the fuel to run rich within the engine, but like everyone whom writes in a topic, they're not sure. so i am wondering if anyone here knows the actual issue or if it is the air sensor, how much would it cost?

[vancouverbc]

Is it running rich during idle or above idle or both? several things cause a rich condition including computer, coolant sensor, mass airflow sensor, leaking injectors, etc etc

by air sensor do you mean oxygen sensor? replace it if in doubt

[831_salinas240sx]

yes, its the oxy sensor. but does anyone happen to know the price of that repair? eitherway it runs rich the minute the car is on. theres a large amount of times that i leave the car on, and go to the back of it, and well, i get a fair amount of raw fuel scent.

[vancouverbc]

zerothread/296414

you just need a 7/8 wrench to screw it out. its around 30 dollars.