2016 Lexus CT200h Experiencing Power Loss, Engine Issues, and Decreased Fuel Economy - Possibly Lambda Sensor Fault?

Hey, got a 2013 Lexus IS 250C and faced pretty similar symptoms as yours. The rough idle, the fuel economy going for a toss, the black smoke...ugg I remember those days. The diagnosis did suggest a faulty lambda sensor but the actual culprit was quite different. Turned out to be an exhaust leak. The garage said that this wasn't something to take lightly. It was directly hampering engine performance and muddling up the O2 sensor readings. So, the strange engine behavior and decreased fuel efficiency made sense. Not to mention, the black smoke was possibly due to inefficient combustion due to the leak messing up the engine's air-fuel mixture. You know, the solution here was as obvious as the problem, get the exhaust system fixed. They patched it up, sorted the O2 sensor thingy and now it runs smooth as a breeze. Also, the old gal's MPG got a significant uplift. Do check for leaks in the exhaust system, not saying your case will be the exact same as mine, but it's worth exploring. Hope this helps and you get the problem sorted soon. Take care!

Hey there, sounds like you had quite the adventure with your Lexus. It never crossed my mind that an exhaust leak could cause all those issues! Fixing the exhaust system and sorting the O2 sensor seems to have made a world of difference for you, huh? Just out of curiosity, do you remember, more or less, how much you ended up shelling out to get everything fixed? And since then, have any new issues come up or has the car been behaving? I'm just trying to get an idea of what's in store for me. Appreciate the help!

Hey, oh that whole ordeal feels like it was ages ago! Yep, the exhaust patch up and sorting out the lambda sensor brought my IS 250C back to life! To answer your question, the exhaust repair came around 265€. Quite a chunk of change, but it did the trick! And since then, everything's been as smooth sailing as it can be. No more annoying check engine light, no more oddball behavior from the engine, and the black smoke is history! You know, it just goes to show, us car guys have plenty to learn. I'll tell you this much - if the mechanics say something is off, it's probably worth looking into. I hated to part with that much cash, but in the long run, it was absolutely worth it. Remember these machines are as good as we look after them. Here's hoping your CT200h comes out of this purring like a kitten!

Thanks for the quick reply! Good to know that sorting out the exhaust and lambda sensor worked for you and it wasn't as pricey as I was fearing. Your old 's resurrection is definitely giving me some hope for my CT200h. It's encouraging to see the check engine light, odd engine behavior and black smoke were all history post your fixes. Absolutely agree with you about us car guys always learning, often the hard way. Mechanics do know their stuff and I'll keep that in mind when I visit. Hopefully, my car, like yours, will come out of this better than ever. Thanks again for sharing your experience. It was a great help, really eases my worries. Cheers!