Toyota Repair: Valve Chatter When Engine is Cold - 2002 Toyota Sienna, low oil pressure, toyota sienna

Question
Valve Chatter When Engine is Cold

Well, our 2002 Toyota Sienna has a valve chatter when we rev the engine above 2500-3000 approximatly when the engine is cold. Just to add to that, the tone of the engine returns to normal after the vehicle has been ran for about 3-5 Minutes. Really depends on the weather conditions.

What is that valve chatter and why is it doing so?

Thanks

Answer
Without hearing the noise myself I don't know whether it's valve chatter or something else.  Most engine noises are related to either low oil pressure or worn engine parts, valves very seldom go out of adjustment on these engines so I think there is something else causing the noise, I would recommend having the toyota dealer look at it, they should be able to pinpoint the noise and make some sort of recommendation, it may be a good idea to just remove the front valve cover to see what the valve train looks like and check for excessive engine sludge.