Knocking/Rapping Noise

[BigMikeT57]

Please help. I am trying to diagnose a sharp knocking or rapping noise coming from the left rear of my '88 420SEL. It happens on acceleration and goes away when I ease off of the gas.

After poking around under the car, I thought the culprit was the
sway bar links, the left side felt loose and clicked when manipulated. So I replaced both sides. Noise went away for 2 days, then came back. Any suggestions?

Thanks,
Mike