O2 sensors issue?

[Ryan Heo]

Hi. My 96 I30 has a bad gas mileages like 15 miles/gal.(premium). It was 20~21 mlies/gal. in the city after all of the O2 sensors were replaced about 3 months ago. So I guess the sensors is something wrong because the car has been showed to the same gas mileage before the sensors were replaced. The two front sensors were from ebay by the bulk type which doesn't have terminal plug. It should be connected with old wire. Are the sensors possible to be broken without any CEL? Thanks.

[NutriaforBreakfast]

You cant go cheap with the o2 sensors

You have to use the three wire type

Several people have complained about the quality of NON-oem sensors like Bosch, etc also. Most say OEMequipment is the way to go

[Ryan Heo]

The sensor has 3 wires. This is the link from ebay.

http://cgi.ebay.com/ebaymotors...ZWD1V

Would you check it for me?Thanks.

[maxhopper]

You need to get one that has the OEM plug already on it instead of cutting and connecting to the old plug - thereby raising the resistance.

[Ryan Heo]

I think so even though the sensors doesn't make any CEL.

Thanks.

[NutriaforBreakfast]

Ryan I wouldnt just focus on the O2 sensors not working

There could be other things

I have read that bad O2 sensors should throw a diagnostic codeif they have a problem

What about a clogged air filter, old spark plugs etc

[Ryan Heo]

The air filter, fuel filter, and spark plugs are the new one.And I don't have any code too.Thanks.