It does not clatter at idle, but once you start driving, there is a clattering sound, not very loud. It used to always go away once engine warmed up, but lately it seems to only reduce. The clatter seems to be associated with how much you press the gas petal, and not RPM. So if you lightly press gas on a warm engine, you won't hear it even if RPM climbs. It's not associated with how fast the wheels are spinning, that's for sure though.

 

Most cars, pressing the gas pedal, increases tire speed, and also engine speed. You description seems inconsistent.

 

Is the clatter more noticeable when the engine is under load, like going up a hill.

Is your car auto or stick

What is the oil level

What weight oil is in the engine

How many miles are on the engine

 

Yes, clatter is more noticeable when engine under load like going uphill.

Auto transmission.

Oil level is normal (half way between L and H.

I use 10w30 Mobil 1 full synthetic.

Engine is 136K miles.

 

I was talking about clatter being cause by something to do with wheels. But the rate at which it's clattering does not increase with faster mph.

 

Drive up the hill in your normal gear.

Shift to a lower gear and climb the same hill at the same speed.

Does the clatter seem faster?
If so, the clatter is probably caused by the engine.

Do you use regular gasoline, or or premium?

 

I use 91 gasoline.
I will try the uphill thing you mentioned.

 

Is the clatter more noticeable if you turn the corner at an intersection? How about a sharp bend in the road?

 

Detonation..? you mention 91 octane.

 

No, I used to have that when CV joints were busted, I replaced those.

 

Yup. That's why I asked. So that eliminates those as a possible course for the noise.