Any help appreciated!
 

I have a 94 civic ex and it's been giving me a bit of trouble. At first it would hesitate while accelerating but only when the car warmed up. Then a few days later it started having idle issues, the car would get really close to dying constantly. Replaced fuel filter, issue left for a day and came back. Replaced O2 sensor and same thing. Today it died when I tried to back it out of the driveway and cranks but no start. Any help would be greatly appreciated, thanks!

Sometimes the fuel pumps fail like this. O2 sensor should not cause no start.

Okay I'll try and pick one up today. Also last time I tried to start it earlier, there was a POP that sounded like it came from the exhaust area so I'm worried maybe the CAT could be clogged...

Certainly a possibility, not sure how you troubleshoot clogged CAT.

Thanks for your response! Will report back after the fuel pump is replaced. Update: no good...

It's usually best to try and test parts versus just buying them. We do our best to advise, but it is the interweb.....

Yeah I probably should have done that. I appreciate the responses. Any other ideas?

Try some basic checks of primary (12v) and secondary (plugs,coil) ignition. Could even be a failing battery or engine timing (seems unlikely).