hearing a clatter at high RPM but not at idle
At first I thought it might be the gas but once the clatter starts it does not stop until the speed is reduced. The noise tends to get louder the longer I drive it. Dealer said it was a small piece in the parking brake release--give me a break! No engine light yet. Without the engine light on will the computer pick up anything?
this sounds like a mechanical problem, it will most likely not set off a diagnostic trouble code at the PCM unless it effects some sensors there for no check engine light. Though it sounds like you may have a valve train problem, such as an incorrectly seating valve, which could be caused by worn valve guides, or worn valve springs which would float the valves causing your vacuum reading to pulse rapidly at idle, you should hook up a vacuum gauge and check.
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