Mazda 6 ('14 Model) Issues: Black Smoke, Engine Shutdown, Decreased Fuel Economy, and Suspected Fuel Pressure Regulator Problem

Hey! Been there. Had similar trouble with my '16 Mazda 3, Petrol one. I'm no mechanic, but I've picked up some car knowledge along the way. Took the ol' girl to the local shop and mentioned your symptoms. They did a diagnostic and found an error code after changing the fuel filter. In my case, it turned out, the car's computer needed to be reset after filter replacement. Local guys sorted it out for me for around 45€. Engine's been purring like a kitten since. Mind you, your beast might have different needs. Do you reckon you could provide some more info, like engine size, maintenance history, et cetera? That’ll help pinpoint the issue more clearly.

Thanks for your input! It's been a little over 138K km since my last service. I've got a 2.5 L engine. The problem started happening not that long after the last service, so something might have been overlooked there, you reckon? Maybe I'll try the computer reset thing you mentioned if nothing else seems probable. Thanks for sharing your experience!

That's a possibility! With routine services, it's not entirely unheard of that some things could be overlooked. I reckon it's a high chance that if the fuel filter was changed at the last service, the car's computer might indeed need a reset. But take my words with a grain of salt, I'm still a car-novice! And remember, another common issue causing those symptoms you've been experiencing, particularly stalling and black smoke, might also be a clogged or damaged EGR valve. That's kind of the emissions watchdog in our engines, and it's more likely to create problems on higher mileage vehicles. Even if the mechanic glossed over it at the last service, the valve may have decided to kick up a fuss since then. Bottom line: get that error code read. Once you know what it says, you'll have a clearer idea of what you're dealing with. Check with your local repair shop. Usually, they can do it for a small charge. Best of luck and let's hope it's an easy fix!

Great advice! I never thought about the EGR valve. I'll get the car to my regular shop pronto and have them pull the error codes while they're at it. Taking on board all of your suggestions I hope it's nothing too serious. I'll drop an update once I know more. Thanks a ton for sharing your knowledge, much appreciated!