Viewer-submitted questions for The Car Doctor: Q: During the state inspection of my 2019 Nissan Rogue, the “EVAP” and oxygen sensor came back as not ready. I changed the battery back in August and ...

Somewhere there's a perfect balance between peak horsepower, low-speed response, reduced emissions, and something you can afford. Variable valve timing and lift have done their part in getting us all ...

Variable valve timing (VVT) and variable valve lift (VVL) have very similar names, both referring to variable valve performance. Does that mean that they are basically the same thing? The are most ...

GM has announced that all V-8 powered Chevrolet and GMC trucks now feature variable valve timing (VVT) for the 2010 model year. A quick trip back to engineering 101 reminds us that VVT is a piston ...

When it comes to the many variables of combustion inside an engine, engineers measure the timing of key events in degrees of crankshaft rotation, a relative frame of reference that remains constant ...

Ducati has announced it will introduce new engine technology that will boost power and torque, improve fuel economy, reduce emissions and won’t affect servicing intervals. Ducati Testastretta engine ...

Valve timing is the most important factor determining an engine's character. A good illustration of this is provided by the following curious historical fact. In 1947 the Standard Motor Company of ...