Check Engine (SES) Light. NEED HELP PLEASE READ. BEGGING YOU

[jnxelectronics]

Ok. So First of all my "Check Engine" light came on about 2 months ago. I left it for it did not really bother me. BUT, found out I am going to Las Vegas, and I need to DRIVE THERE. Now I know it will make it EVEN with the light, but my GAS has dropped A LOT. I got it "scanned" at auto zone and they sid it was code PO171, and they said it was my Bank 1 O2 Sensor. Changed it, and it CAME BACK ON. Got it "scanned" by my boy, who said Bank 1 AND Bank 2 O2 Sensors were bad, and this was AFTER I changed out my O2 Sensor. Then his machine ran a test on ALL SENSORS, it came out the Bank 1 and Bank 2 were working Fine and it showed my TPS (throttle position sensor) as bad (having ZERO readings), so I changed that out, reset my light, and low and behold it cme back on today. Now here are the "symptons", It is Hesitant AND Vibrates when I try to "launch", BAD gas mileage, Rough Idle and can smell from the exhaust that it is RUNNING LEAN. I need HELP. I am BEGGING ANYONE out there. PLEASE list ALL POSSBLE reasons, I do NOT CARE IF IT IS A 1 IN A MILLION SHOT, PLEASE HELP ME BEFORE I GO TO NISSAN AND PAY THEM TO "SCAN" MY ENGINE. I am thinking it is my MAF????/ ANyone else.

[gwhunt23]

MAF seems like it could be a good bet. It's a spendy item to replace if you're not exactly sure that it's the culprit. You can try some electrical contact cleaner lightly sprayed on the sensor (available at your Autozone or equivalent) or you can try picking up a used MAF from a Maxima as they're usually about a third the cost of one off a Pathy.

Also keep in mind that when changing O2 senors, Bank 1 corresponds to Cylinder 1, which means bank 1 is passenger side (in America at least! )

Also another thing to note about O2 sensors. There are four in your vehicle, but I only see you referring to the senors of Bank 1 and Bank 2. The scan tool should also report the sensor number, if it is sensor 1 it is upstream of the cat converter. If it is sensor 2, it is downstream of the cat converter. Hope you were indeed replacing the correct sensors all along!

[jnxelectronics]

Na man. Auto Zone said BANK ONE was driver side. That make ****ING SENSE. For AFTER I changed my Driver side sensor with a BANK 1 sensor, the computer kicked out BANK 1 AND BANK 2. Before that it was ONLY kicking out Bank 1. So I need to CHANGE my sensor location from Driver side to Passenger Side as well as buy ANOTHER Bank 2 "driver side" sensor, for I threw that one away. You think taht would work?

[jnxelectronics]

But just curious, are the FRONT LEFT and FRONT RIGHT INTERCHANGEABLE? For I really do NOT want to take out my Front left O2 Sensor, it was a *****

[gwhunt23]

I'm not sure about interchangeability. Maybe fueler or someone can chime in on that.