O2 Sensor
 

Quick question, my car is running sluggish. I have no check engine light, ran my OBDII scanner and no fault codes.

Does a faulty O2 sensor ALWAYS trigger a check engine light or a code?.

Can a faulty O2 sensor or sensors cause my car to run sluggish, poor throttle response?.

Thanks....

have you tried cleaning the MAF sensors?

A faulty O2 sensor can cause problems but I don't remember reports of one affecting performance without throwing a code. You may be able to monitor output with your OBD tool; normal operating values should be in the FSM (link in my sig).

Check your Intake Air Temperature (IAT). The ECM limits power when it gets over about 90 degrees F or so. If temp is OK, I'd try cleaning the MAFs, as per Z_ealot.

You are probably experiencing the summer choke as I call it. The IAT's are so hot the car acts funky in heavy traffic or just after a hot re-start.

I have had and seen several vehicles Ford's,Dodge's,Kia's,Hyundai's and Suzuki's etc. that had faulty 02 sensors but, just exhibited all the signs of having a faulty 02 sensor/s .I never seen any Nissan or Infiniti that would not tigger any check engine light when 02 sensor/s were faulty as the pcm in these vehicles are very efficient at detecting faulty codes. There are a lot of different reasons why your car could be running sluggish or have poor throttle response not just from having faulty 02 sensors. You are not supposed to wait until your 02 sensors fail to replace them. A Nissan dealership service department told me you should replace your 02 sensors every 60k or 5 years whatever comes first because it is part of a tune up service to replace your 02 sensor/s. What is most important about the 02 sensors is they report to your PCM current conditions of your air to ratio. You should be have your car diagnosed. Have you been doing all the general maintenance on your car? Not only could you possibly have faulty 02 sensors but, other things could be wrong with your car. You could have a clogged internal fuel filter in your gas tank, your air filters could be clogged, you could have vacuum leak/s, your pcv valve could be clogged,you could be in bad need of a full tune up spark plugs,coils,pcv valve etc.

Thanks
 

Appreciate the input, but the car has 9000 Miles on it with new filters oil...the works.

I think I am experiencing the dreaded lethargic throttle response under 3000RMP

Found out it's been heavily documented on here back when the model was new...

Maybe an ECU tune will fix the crappy throttle response.