Hi, my car started making a rattling noise, definitely from the engine. Not noticeable when cold but soon starts even when half warmed up. It's present when accelerating or holding a steady RPM but not when the gas pedal is released. It's there from 1500 RPM to 4500 RPM. The car has 37100 miles and has full dealer service history. Took it back to the dealers and they diagnosed a faulty valve lifter. They replaced all 12 lifters free of charge and the problem is exactly the same. The car is out of warranty and they did that on goodwill so I'm going easy on them as they say they're going to fix it no matter what. The noise can be heard at freeway speeds, if you're stationary and rev the engine or travelling at low speeds. Any ideas? Cam sequencer (vvt), Timing chain? Anyone else had a similar problem?