From my experience i got the same problem. I used shell 91 octane and my z started to ping in very low rpm usually while taking speed bumps in second gear close to 700-600 rpms and a loud ping went starting the car in the morning. I change to Puma 93 octane the only gasoline available with 93 octane and the ping was gone. No ping in speed bumps or cold start ups. I thing the z is tune for 93. I prefer shell better than puma here in Puerto Rico but shells doesn't have 93 oct.
|