Welcome to the wonderful world of Knock Retard. The ECU is pulling the timing to avoid engine knocking and you feel it as pulses in the throttle. This also causes the car to waste fuel by burning it at a non-optimal point in the cylinder/piston cycle. Increasing the octane until the pulsing is gone will boost fuel efficiency and throttle responsiveness.my car will pulsate on 87 so ive been using 89 with little to no pulsating. a/c use is when the pulsating was most problematic on 87.
For most cars you are wasting money running higher octane than needed. Even with the Cruze some of our members have discovered that mid-grade is sufficient so they would be wasting money going to premium.Agree totaly! I know many people say you're wasting your money and that it realy makes no diferance but for me and my Cruze we will use premium!