Engine Knocking

2002 Chevy Trailblazer Lt with 167,000+ miles. The problem of engine knocking has since come about after I drive 30 miles or more at 65-70 miles per hour.

When decelerating and coming to a complete stop
the engine knocks like it has no oil. Once engaged back into normal in town stop and go driving, the knoocking disappears and the engine runs as it should.

The engines oil pressure gauge registers normal. No evidence of engine sludge, No loss of engine power.

I have noticed a moderate to severe vibration coming from the car while idling in drive but I don't know if this is in any way related to the knocking issue.