Doe's anyone else find when they use regular unleaded fuel the car idles/vibrates more, when i use premium it idles better?

This sound common or not normal?

And spark plug leads, do these affect the way in which a car idles if there getting old?

well I will never run normal unleaded again unless desperate, runs **** box on it, Only premium from now on

Hello,

All Jap cars (Engines) like 95 To 98 Octaine!!

Use BP Ulitmate Or Opitmax you cant go worng.