Toyota 1ZR-FAE

Toyota's 1.6 Valvematic — in the Corolla and Avensis, and, unexpectedly, in the Lotus Elise S3.

The FAE suffix is Valvematic, and it is the whole character of the engine: a mechanism that varies how far the intake valves lift, so the throttle plate does less of the work. It is not variable timing — the ZR family has that too, separately — and confusing the two sends a diagnosis to the wrong actuator.

A rough or hunting idle is the complaint that brings these in, and the Valvematic controller and its motor are a genuine cause rather than an exotic one. But carbon on the intake valves produces the same symptom, and on an engine whose breathing depends on valve lift it produces it earlier than on a conventional four. Clean before condemning.

The mechanism is oil-fed and oil-sensitive. Neglected servicing shows up here before it shows up anywhere else, which makes oil history the first question rather than a formality.

The Lotus fitment is the same engine in a very different car, and the useful consequence is that Toyota parts and Toyota diagnostics apply — as they do to the 2ZZ-GE in the earlier Elise, which has a page here of its own.