95 Z28 Pinging

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.

Is it normal to hear some pinging before the knock sensor kicks in?

Any ideas?

Reply to
Danny
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I am using Chevron and/or Union 76, 89 octane premium gas.

Reply to
Danny

Where I live in California, Premium is 91 octane. My 96 Z28 runs fine on 91. Even going uphill with the AC on when it's 105 degrees outside.

Reply to
Gary - KQ6RT

your best case scenerio is the timing is off, but it sounds like the motor might be knocking on heavens door. how many miles did you go in between oil changes?

Reply to
Hitman0187

It went about 4,000 miles between the last oil change.

Reply to
Danny

My mistake, you're right, our premium gas here is 91. I believe though a few years ago it was lowered from 92.

Reply to
Danny

What part of CA? Here in Sac - and in all outlying areas I've been to - premium is 91 (wish we had 93-94), plus is 89.

Reply to
7ball

What part of Sac are you in? I live in Newcastle, but I work in Sac. - Gary

Reply to
Gary - KQ6RT

North Sac, between Rio Linda and Antelope (Elverta).

Reply to
7ball

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