need some help here i read up on some write ups and still got a few questions

my 2000 tl waistes alot of gas not sure why but when i first got it i put 30 in 87 fuel my dumb ass not knowing so i burnt it.car was runnning funny but now i mix it up some times between 89-93 do you think that is cuasing the car to throw those codes?

 

what exactly does this mean?

p1456 -Leak Detected In EVAP Control System

<LI class=odd>P0420 – Catalyst System Efficiency Below Threshold (Bank 1)

 

,p1456...evap system small leak.....99% of the time is the gas cap leaking.....i see this at least 10x a day at work. Check the oring seal on the cap, make sure its not cracked dryrot or distorted. If you have a scanner or go to discount and have them clear it. And the p0420, cat converter could be starting to fall apart on the inside, or since you ran 87 octane, pcm could have tried to compensate for lack of octance, ran lean and saw an excess amount of O2 in exhaust...........get some higher octane fuel and clear the codes....go from there.....both codes are not uncommon, i see them in older/higher mileage Hondas everyday

 

werd thanks playa ima goo and look in to that today i filled up with 93,and if i wanted to do a tune up what would i have to buy and replace ?