Rep Power: 0

2001 Civic, 170,000 miles.
My Malfunction indicator light have been coming on and off for a couple weeks, yesterday I lost all acceleration (idle mode?) and had to pull over for a bit. While this happened the light came back on and started blinking. My acceleration has been sluggish for for awhile as well.
I took it to autozone today and got the following codes.

P0300
P0301
P0302
P0303 - misfires

P0131 - o2 sensor
P1457 - emissions leak

The plugs, wire, coils and catalytic converter are all about 18 months old. Before I just started replacing everything again, I was wondering if anyone could shed some light on whats going on.
I don't think my plugs are bad. I think I will start with the o2 sensor and see if I keep getting the misfires. Could that have anything to do with my emissions leak?
How risky is it to drive with these problems?

Thanks for any input!

 
Rep Power: 200

Plugs are the likely culprit honestly. Find your emissions leak and go from there. That is the cheapest route. Adress the 02 code and go from there.

 
Rep Power: 189

Start with your plugs-they're cheap. Plus if you continue to drive with misfires you're going to fry your new cat.

 
Rep Power: 200

True, misfires dump fuel or run too hot and eat cats.

 
Rep Power: 0

replaced the o2 sensor and the plugs. pretty sure my cat is gone, their are holes where pipes connect to the converter, think ill try weld this to see if I can prolong it a bit more. Thanks for your help