My 95 Z, 58k miles is pinging on acceleration when going up a grade on the
freeway, especially when a/c is on and/or when I am carrying a passenger and
on warm days 85+ degrees.

The pinging was reduced considerably after a recent oil change, however when
I took it in to the dealer shop, they put it on the computer, everything was
perfect they told me. They test drove it after the oil change and it did not
ping for them, same 'ol story. They told me if it happens again to bring it
right in for a test drive.

I asked them to check the knock sensor, but has they said the computer did
not show anything wrong, everthing was up to spec.

Any ideas?