Siena rough running exhaust leak

Whoa, sounds frustrating! I had a similar problem with my old Opel Astra, although it was a diesel. Check engine light, the whole shebang. Turns out it was a tiny leak in the exhaust system, causing all sorts of mayhem with the oxygen sensor readings. The engine was basically choking itself because it thought it was getting bad air. Made it run super rough and jumpy, especially when accelerating. Have you checked your exhaust system for any cracks or leaks?

A leak in the exhaust system, huh? That's interesting! Where exactly was the leak on your Astra? Was it easy to spot, or did you need special tools to find it? I'm willing to get my hands dirty, but I'm no mechanic. And would that explain the error codes, or is it more likely something like a faulty oxygen sensor giving false readings?

On my Astra, the leak was near the catalytic converter. Honestly, I couldn't see it myself. I took it to a workshop, and they found it with a smoke test. They plugged up the exhaust and pumped smoke in to see where it came out. It's probably best to get it checked professionally, especially with the error codes popping up. Could be the sensor, but a leak can definitely mess with those readings too. Save yourself the headache and get a proper diagnosis.

Okay, I hear you loud and clear! Workshop it is. Just got the car back. You were spot on – a tiny crack in the exhaust manifold! Cost me 265€, but the Siena is running smooth as butter now. Thanks a million for the tip; you saved me hours of fruitless tinkering and a lot of anxiety!