Another check engine light question

[Heavy D]

After installing a new exhaust on my '95 240sx, the check engine light came on. I'm assuming this is because the new high-flow cat is now behind the second O2 sensor. I can make the light go off temporarily leaving the battery disconnected overnight, but it always comes back on within a week or so. If I were to just leave the light on until I can get the O2 sensor moved behind the cat, would it present any performance or gas mileage problems?

I know this has been asked a thousand times, but no one has really covered what will happen if the light is just left on due to this issue.

Thanks for not hating/flaming

[ricebike]

i don't believe it would cause any performance/mileage problems.

since the 2nd o2 sensor's main function is to check the efficiency of the cat, i doubt that the car's pc would retard the timing or whatever to adjust for it.

you'll b fine.

[TigerBill]

Heavy I'm having the same problem, since a high flow cat install. Have you ever had your engine codes pulled? Mine says something like running rich, or some crap. I get a knock sensor code every now and then. But I mostly just let mine stay on till I make a trip to Autozone they pull codes for free and resest the light.

[Heavy D]

TigerBill,

No, I've never checked to see what code the ECU is throwing, since the car runs like a top. I just assumed it was the stupid cat. I guess it couldn't hurt to have it checked, but I'll just get the second 02 sensor relocated eventually.

[TigerBill]

Yeah I never worry about it, because my car has been runing great and I've been getting great gas mileage for how I drive.