How could anyone fix the problem of 1998 Chevrolet Malibu's Pas-lock ?

First of all I thank all the help we could get; we have try follow the rule for take care newer cars; such as when turn the ignition key; slightly depress; and every time refill the gas tank remember making sure turn the cap couple turns; moreover we try to make sure the gas pump relay is in functional and conduction; and the problem of Pas-lock went away; but are there anything else could be done to ensure this problem has been fixed; because many friends posted the same problem on this web page, and it seems that now is our turn to encounter the same problem on 1998 Chevrolet Malibu. Thank you again for any help.