+1 , do not run 87 octane gas - use at least the 91
also , reading your post about being low on gas
never , never get happy with the right foot when the tank level reads 1/4 or lower
the fuel slosh away from the pick up will cause the engine to run lean

the sticker on the fuel door should read premium fuel only
with a stock log turbo motor I used to get excessive detionation just driving up hill gently so getting on the gas hard is only likely to damage the engine with the 87

the difference in fuel cost between 87 and 91 or 3 should show a return in increased mileage per gallon