Toyota Quietly Went Back to an Old Engine Design in 2005 — Here’s WHY

In 2005, Toyota quietly went back to the old design. On a brand new 3.5-litre V6 for the Lexus GS 350 and IS 350, it added a second fuel injector to every cylinder: an old-fashioned port injector, the kind the rest of the industry was busy throwing away. No advert, no recall, no letter to owners. The reason was a problem built into direct injection itself. With the injector moved inside the cylinder, petrol never washes the intake valves, and oil vapour bakes onto them as carbon. Most of the cars on British driveways never got Toyota's fix, and their owners are the ones paying for it. This video covers how port injection kept valves clean for decades without anyone noticing, why the industry raced to direct injection after Mitsubishi's 1996 launch, and what a 2011 Chevron Oronite study actually found in the deposits. Not "ten times more carbon", but at least ten times more of the minerals that come from engine oil. Then how Toyota's D-4S system shares the work between two injectors, and the twist inside its own showroom: the cheaper Lexus IS 250, launched the same year without the fix, and the carbon programme Lexus ran for it in 2012. Then the British cars that never got it: the Mini Cooper S and the Peugeot and Citroën THP engines it shared, BMW offering walnut blasting on its own direct-injection cars from 2006 to 2016, and turbocharged VW and Audi TSI and TFSI engines. What the clean-up costs here, from around £240 at one Mini specialist to £800–£1,500 quoted on one Audi owners' forum, and why it can need repeating every 30,000–40,000 miles. Plus how Ford, VW and others quietly copied Toyota years later, and the honest side: direct injection delivered real gains, and one trade magazine says Ford and GM engines draw hardly any carbon complaints. How to tell from the badge on your boot whether your engine is direct injection, what to check before buying used, and an open question about the Jaecoo 7, Britain's best-selling car last month. Do you own a Cooper S, a Peugeot or Citroën THP, a TSI or TFSI, or a direct-injection BMW? Has it ever needed a carbon clean? Tell me your car, your mileage and what it cost in the comments.