Metric size. Probably 17mm. Try your metric sockets until you get the correct size.
The fuel tank capacity of a 1991 Honda Accord is approximately 17 gallons.
17 gallons
6.5 fron and rear
195/60 r15 87h
The 2009 Honda Accord has a 2.4 L base engine size.
The 2013 Honda Accord has a 2.4 L base engine size.
The 2001 Honda Accord has a 2.3 L base engine size.
The 2011 Honda Accord has a 2.4 L base engine size.
The 2005 Honda Accord has a 2.4 L base engine size.
The 2006 Honda Accord has a 2.4 L base engine size.
The 2010 Honda Accord has a 2.4 L base engine size.
The 2014 Honda Accord has a 2.4 L base engine size.