2002 SL2 - Engine Pings...

I have a 2002 SL2 and whenever I am driving and the engine is under load, there is a pronounced pinging noise coming from the engine. The oil level is correct and I just changed the spark plugs and set the correct gap. I use 87 octane fuel (which is recommended) and it happens even if I use different gas stations...

Does anyone know what could be causing the pinging or what I should look at?

Thanks!

The engine has a 'knock sensor' on it, and it has probably either failed or the connector or the wire to it has gone bad. I think the sensor is on the rear of the block, visible from underneath. Inconvenient location!
In your shoes, I would be using a higher grade of gas until I got it fixed. The pinging is really hard on your pistons. Overheats 'em.

Its very rare the knock sensor fails and does not light the SES light. Make sure when the key is in the RUN position before start up that the SES light turns on. You could have a DTS code and a burnt out bulb and not even know it.