Mazda '06 Model: Engine Power Reduction, DPF Regen Failures, and Possible Faulty Exhaust Gas Temp Sensor Issues - Seeking Advice and Trouble-shooting Tips

Hey there, sounds like you've got a bit of a pickle! Just a few years back, I dealt with a similar issue on my '04 Mazda 3, petrol engine too. Now, I'm no mechanic but I've got some experience tinkering around under the hood. Had the exact same problem - the funky smell, reduced power, the works. After a couple of failed home fixes, I finally took it into my local shop. They confirmed that the issue was indeed an exhaust system leak, as you suspected. Cost me about 265€ to get it sealed up properly, so not too bad on the wallet. Your Mazda 5 might be suffering from the same. At the same time, it's hard to say for certain unless we know more details about the car - its mileage, where you usually drive (urban settings, highway, etc.), and if you've made any modifications recently. Hope that helps and let me know if you have more questions. A stitch in time, eh? Good luck!

Hey, thanks for the quick response! My Mazda 5 has been quite a road warrior with 270759 KM on it, mostly highway miles. No recent mods made, I like to keep her as original as possible. Tried doing an ECU reset after my last service but it seems to be persistent. I really hope it is as you say, just an exhaust leak. I'll run your suggestion by my mechanic and see what he says. Hope it won't burn a hole in my wallet! Cheers!

Hey, your Mazda 5 sure has some miles on it - respect for keeping it all OG. I reckon the highway miles and the ECU reset you tried could've stirred up the DPF issue further, causing the temp sensor to go a little haywire. Additionally, the leak might throw off those exhaust gas sensor readings. I would advise you to get the exhaust system checked thoroughly, ensure the DPF isn't blocked up and your exhaust gas temp sensor is functioning properly. Make sure they also do a smoke test to find out if it’s leaking. It was a relief when it was just the same issue for me, but having a highway warrior might call for some more tinkering. Good luck! Don’t stress too much about the wallet. It may cost a bit but I'm sure it’ll be worth keeping the old girl running smoothly. Keep us updated on what unfolds!

Ah, that does shine a light on things! I think you're spot on about the ECU reset and the DPF issue. I'm heading to my mechanic first thing tomorrow to get everything you suggested checked out - the exhaust system, the DPF and the godforsaken temp sensor. I'll also ask him to run a smoke test to check for leaks. Thanks a ton for your suggestions! I'll keep you updated about what happens. At this point, I just want her running like she used to, without that check engine light glaring at me! Fingers crossed it's not gonna be hard on the wallet. Cheers!