Supra IV engine running lean

Hey, I'm having a weird issue with my 2021 Toyota Supra IV, gasoline engine. It's got 167569 km on the clock. Lately, the engine feels like it's running lean. I've noticed a definite loss of power, the check engine light is on, the engine runs rough, and it even jerks a bit when I try to accelerate. I'm not a mechanic, so I've only checked the obvious things like making sure the air filter isn't completely clogged. Any ideas what could be causing this?

4 comment(s)

Hey there! I drive a Supra IV too, though I haven't had the lean running issue quite as severely. But, those symptoms sound familiar. Did you check the spark plugs? A dodgy mass air flow sensor could be a culprit too. It's like the 'brain' that tells the engine how much air is coming in. Otherwise, the throttle body or intake manifold could be dirty, but it would be very obvious. Keep us posted!

Thanks for the quick reply! Spark plugs are something I can check myself, I'll do that tomorrow! Where exactly is the mass air flow sensor located, and how would I check it? And should I consider cleaning the throttle body? Is it something I can do, or do I need special equipment for that? Is the oxygen sensor also a possibility?

Okay, so the mass air flow sensor is usually located near the air filter box, connected to the intake. There are videos online of how to clean them, but honestly, if you're not sure, it might be best to leave it to a professional. Also, the throttle body can be cleaned but I'd advise you to be very careful not to damage it. Given the engine light and jerking, I would just take it to a workshop. It could be the injection valve/injector, and that's often difficult to do yourself. Better safe than sorry!

Thanks so much for the advice! I took your advice and brought it to a mechanic. Turns out you were right on the money! It was indeed a defective fuel injector, resulting in the engine running lean. The repair cost me 515€, but now she runs like a dream! Thanks again!

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