Depending on the model and year, you may have a bad knock sensor. The 90 and later ones have a knock sensor that retards the timing to eliminate the knock, but you really are better off with premium, you get much better power and less knock.
Also check for a bad O2 sensor and vacuum leaks, as lean running will also cause knock the computer can't fix. Volvo's are supposed to be as good as Benzes in crashes, although I'm NOT going to voluteer to test mine, it's someone else's turn! Peter _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com