this is a set of questions about spark plugs...i want to diy all the things that i can diy with my car...i hope the gurus here can help me..TIA

+ how would you know when to clean or replace plugs?

+ when you found out that you need to change the plugs, what would be the best choice? e.g. brand of plugs, etc (my ride is a lancer 1.3)

+ after choosing the right plugs, how would you if a certain brand of plug is genuine?

TIA po sa lahat ng mag rereply...all responses will be higly appreciated!