2010 Toyota Sienna Experiencing Power Loss, Black Exhaust Smoke, and Poor Fuel Efficiency

Hey there, Sounds quite a bit like the issue I had with my 2013 Toyota Highlander not long ago. Around 65,000 KM on it and similar symptoms, same black smoke from the exhaust, engine check light was always on, and felt like I was driving a tractor rather than a car. Did some home diagnostics and thought the same as you - Lambda sensor being the culprit. Took it to my trusty garage, and my suspicion was confirmed. The problem was the ceramic inside the Lambda sensor had gotten dirty, which led to it malfunctioning. It was affecting the car’s fuel-air mixture, hence the black smoke, rough ride, and crummy fuel economy. They had to clean the ceramic inside the Lambda sensor. It wasn't a quick fix, as they also had to check and confirm that the sensor was still working correctly after cleaning. It can be a serious issue if left unattended so it’s good you're trying to sort it out. So yeah, sounds pretty similar to what you're going through. Hopefully, that gives you a better idea of what you might be facing. Best of luck!

Hey there, Appreciate you sharing your experience, seems like my hunch about the Lambda sensor might be on the right track. Sounds like quite a ride you had with your Highlander. Just out of interest, do you recall about how much you ended up paying at the mechanic's for the fix? And I'm curious, after that issue was taken care of, did anything else pop up or has your car been running smoothly since then? Any info would be great. Cheers!

Hey! No problem, happy to share. For the Ceramic inside the Lambda sensor cleaning, it set me back €375. Not the cheapest, but considering what a pain the problem was, it was worth every cent. And to answer your other question, since they cleaned and fixed the Lambda sensor, my Highlander has been working like a charm - knock on wood! It's been smooth sailing, no black smoke, no check engine light, and the fuel economy is back to normal. Nothing else has cropped up, so I'd say getting that issue sorted definitely did the trick. Hope this helps, and good luck with your Sienna!

Hey! Thanks so much for the detailed response and for sharing costs as well. €375 isn't small change, but as you said, resolving such a troublesome issue is definitely worth it. I'm relieved to hear that fixing the Lambda sensor helped and your Highlander has been running great since then. This conversation has set my mind at ease a bit. I'll look for a trustworthy mechanic to inspect the sensor, clean it and get my Sienna back to work. Cautiously hoping it goes as smoothly as your experience. Thanks again for all your help. Take care!