So last Saturday I changed my spark plugs for the first time @ 103K miles with NGK Platinum OEM replacements gapped at .044. Also changed the oil with Mobile1 High Mileage and put a new Cone Filter on.

After the maintenance I put everything back together, car started right up and then I reset the ECU using the pedal method. Car Ran great.

On Monday night I got on it after leaving the Gym and the car immediately went into LIMP mode. I reset the ECU using the pedal method and it went away for a couple of miles then came back. Turned the car off waited a few minutes then turned it back on – LIMP mode went away.

Plugged my OBD2 scanner in and on the way to work today I finally got the monitors back on and as soon as they came on I got code P1271 & P1281 and the car went back into LIMP mode.

I know P1271/P1281 means A/F Reader (sensors in Exhaust Manifolds)
Checked all vacuum lines with carb cleaner and found no leaks.
I’m reluctant to think it has anything to do with the new plugs because the car ran fine when I started it up after the change.

I have been running Test Pipes, Greddy Exhaust, CAI and Synthetic Oil for over 50K miles and never had a problem going into LIMP mode before. I’m the original owner and never beat on the car.

My question is, has anyone else had this problem and is it really these sensors or something else? This has been and still is my DD so I need it running well.

Thank you in advance for any comments.

 

If you are having misfiring issues, I would look at the coils/wires. If not I would look more around the Mass Air Flow sensor. Most likely you disturbed something while doing maintenance. Leak between MAF and throttle body, disturbed electrical connector, etc.

 

Thanks for the reply. I'm not having any misfiring issues and not throwing any codes for the MAF sensor, throttle body or Coils. The LIVE data on my OBDII shws them working as should but I am getting the codes for the A/F ratio sensors in the manifolds.

I'll Triple check all of those connections tonight though. Just don't know if it's a coincidence that that these sensors went the same time I did the maintence or if there is something else causing these codes to come up.

 

 

I have had those codes and it had nothing to do with the oem 02 sensors. In my case it was caused by exceeding the oem MAF air flow due to overboosting. My situation has nothing to do with a N/A car except to explain that in my case those codes were not caused by 02 sensors.