R redacle2 New member Aug 25, 2009 #1 I drive a 2004 focus PZEV 2.3L. With 87 octane, there is no engine knock but the engine feels more rough, especially when it idles. So I usually fill 89. Will this damage damage my engine? I can't find a proper manual to this car.
I drive a 2004 focus PZEV 2.3L. With 87 octane, there is no engine knock but the engine feels more rough, especially when it idles. So I usually fill 89. Will this damage damage my engine? I can't find a proper manual to this car.
