Fortuner Diesel Rough Idle Fuel Injector Issue

I understand your concern, especially with those symptoms. Given that it's a diesel engine, gasoline contamination is unlikely, though not impossible. More probable culprits are issues within the diesel injection system. Are you noticing any unusual exhaust smoke? Has the fuel filter been changed recently? Poor starting, high fuel consumption, reduced power, and uneven idling all point towards potential problems with the fuel injectors, potentially due to fouling or wear.

No unusual smoke that I've noticed. Fuel filter was changed about 10k km ago. What exactly would be wrong with the injectors? Is it something I can fix myself?

Given the symptoms and the mileage, it's plausible that one or more of your injection nozzles are defective, likely due to fouling. While cleaning fuel injectors can be a DIY job with the right tools and knowledge, improper handling can seriously damage them, leading to much bigger problems. Considering the potential cost of replacement versus professional cleaning and testing, I highly recommend taking your Fortuner to a qualified workshop for diagnosis. They can accurately assess the injectors' condition and recommend the most appropriate course of action.

Thanks, that confirms my fears. Took it to a shop, and they found one injection nozzle defective. They cleaned all of them and replaced the bad one. Cost me 515€, but it runs like new again!