If anyone knowledgeable on the topic happens to find this…

I think we all become complacent with deteriorated performance of parts over time; after all most parts don’t break right away, and wear down slowly.


I’ve noticed that my car has become quite “sluggish” and does not seem to have a lot of power to bring it up to speed nor when I let off the gas does it seem to come back to idle quickly.

I also noticed a very random, occasional “stumble” that feels like a engine vibration maybe occurring once ever 2 minutes. Ignition components are good, vacuum lines and idle speed are good; fuel system is good.

I ran car scanner with the WiFi OBD connection on my car while driving and I noticed that the Upstream O2 sensor swings quite significantly in comparison to the downstream (see the attachment) and I am wondering if this may be the culprit.

I understand some fluctuations are expected, but more than 0.1-0.2V? That’s approx 10-20% of the sensors range already so I doubt it…

Keep in mind my O2 sensors are original, car has 220k miles. 😎

Check out the reading attached; this is car stopped at a light, in drive.


Thoughts?

 

I'm not sure about those graphical data but I did have that "sluggish" acceleration about 6 years ago and it was that O2 sensor.. after replacing, my car got smooth again.