HELP! Error codes P0420 and P1457

[derekryans]

I'm no mechanic...just a kid who wanted a better car. My last car was a civic hatch and had horrible gas mileage so I traded it in to a friend who sold me a 99 Civic Si but did a motor swap with a Civic EX. The engine is D16Y8. A little history is that I got the car they told me that the shell itself sat there for a little while but the motor came out of a running car. My friend told me to do a tune up so my dumba** listened to him. Well it ended up that somehow the fuel filter corroded the inlet line and uh...well it broke. The damn thing broke off completely! So it got towed to Pep Boys and 300 dollars later it got a new fuel line. Then i figured since i already spent the money I might as well finish the tune up. Well, I was in a hurry and accidently messed up the firing order. So once that was fixed i thought YAY relief! But no...the check engine light came on. Took it to autozone, they said it was error P0420 and said it might be a bad sensor, the 1st one. So then I looked for the sensor, it was sitting on the exhaust manifold, replaced it with a Bosch universal cuz I didn't have money to buy the OEM from Honda. I noticed that the OEM connector was kinda lose (the wires kept coming out of the connectors) but my friend and I plugged it in and it seemed to stay tight. Two days later, check engine came on AGAIN. My friend pops the hood and then realizes that the fuel filter kinda leaks a little so he tightens the banjo bolt. Oddly, the CEL went off. Then today, the damn thing came on again. So i was at autozone once again they checked it and this time gave me three codes. One was P0420, and the other two were P1457.

Save you guys some time, since i got lots of questions...I'M SORRY!

P1457 = EVAP Emission Control System Leak Detected (Control Canister System)
***At autozone it was this error but it also said auxillary something...sorry I can't find the exact phrase anywhere...***

P0420 = Catalyst System Efficiency Below Threshold (Bank 1)


I've been searching around on these forums...do I need a new catalytic converter? Somewhere I found that when cats go bad the exhaust makes a rotten egg smell? I smelled it...(yup again, im a dumb dumb kid) it doesn't smell like rotten eggs. Another site also indicated that there might be a crack in the cat...ima have my friend check it out for me tomorrow and see if it's that.

Main question is, can someone please help me take care of this CEL problem once and for all?! Not only is it scaring me, i've noticed a serious decrease in gas mileage. Also, it takes a while to accelerate...like the car's dragging something.

Another few questions, although they're not as important as the above question.

1. my gauge light is out. changed the bulbs. didn't work. i wanna test the dimmer switch...but um...how do i do that? i have a ohmeter thing but don't really know how to use it.

2. the dumb f**ks who painted my car shaved off the antenna and i have no radio...can i reinstall that?

3. my speakers in my car goes in and out...ALL of them. do i maybe just need new wire connections? (they're rigged the ghetto way without plastic connector pieces.

Again, I apologize for my questions. I really wanna do everything on my own or with my friend because I don't have much money...any help anyone can offer me is greatly appreciated. I tried calling honda and all i get is 130 diagnostic fee and if its the cat it's 800 and if it's the 02 sensors is 300 blah blah blah so on so forth. i hate dealerships but i hate even more that i don't have the knowledge to do it on my own...