What about the Yaris I a?

[Kalispel]

Originally Posted by Hershey

Bronsin , make sure your son in law uses a Top Tier gasoline for the Yaris Ia at all fillups . It's highly recommended for D.I engines . Here's a list of Top Tier gasolines . https://www.toptiergas.com/licensedbrands/ . The use of TOP TIER gasoline is likely in the owner manual . Have him look it up . Its stated in the '11 FIT owner manual ( below ) . The FIT is E.F.I. .

With pure direct-inject engine designs (like Mazda uses - and most other automakers for that matter), even top-tier gas will only address HALF the carbon buildup/deposit problem. They are simply flawed engine designs from a reliable, problem-free consumer ownership standpoint. Direct injection needs to be paired with port-injection to address the whole issue adequately, with regards to top-tier fuel detergents keeping carbon deposits at bay across BOTH problem areas. Toyota was smart enough to do just that with their new TNGA 2019 Corolla engine design. That's also another reason to LOVE the venerable non-direct-injection 1NZ-FE engine still being used in the Yaris.

[IllusionX]

Originally Posted by Kalispel

With pure direct-inject engine designs (like Mazda uses - and most other automakers for that matter), even top-tier gas will only address HALF the carbon buildup/deposit problem. They are simply flawed engine designs from a reliable, problem-free consumer ownership standpoint. Direct injection needs to be paired with port-injection to address the whole issue adequately, with regards to top-tier fuel detergents keeping carbon deposits at bay across BOTH problem areas. Toyota was smart enough to do just that with their new TNGA 2019 Corolla engine design. That's also another reason to LOVE the venerable non-direct-injection 1NZ-FE engine still being used in the Yaris.

An oil catch can should keep the intake valve pretty clean.

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[Kalispel]

Originally Posted by IllusionX

An oil catch can should keep the intake valve pretty clean.

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Shouldn't Mazda (& others) be doing that from a design & factory-build standpoint? It should be standard equipment for straight GDI engine designs, if they care anything about building a reliable, trouble-free engine that stands the test of time.