Strange Stuttering and low idle

[inlinedude2]

Hi, im new to here and i stupid when it comes time to work on cars. i have a 98ZX2 5 spd for about a year now. since i've gotten it its done this weird stutter when i accel and drop to 500 RPMs at lights. it doesnt do it all the time, VERY VERY random times. i have a cold air intake since ive gotten it. recently put on a pacesetter header and pipes, left cat there. i'm told to knock it out to make it louder but debating on that. but iv'e fixed everything i'm told could be the problem but still does it. what it does is in ANY gear i'm in if i slightly press accel it will stutter along for a bit then kick in and go. and if i'm at a light or sign the RPMs will drop to around 500 and try to die off. i still have the check engine light on but i'm told its due to O2 sensor. so i wanted to ask if anyone would know how to make it stop, if that is the problem or something else. the O2 sensor has only been reading since i put on header and pipes so thats why u question it. otherwise i'm out of ideas, thanks for your help

[inlinedude2]

also, i know its odd b/c its a ZX2, but i plan on making it faster, so if any1 knows any good places to get parts for it that would also help. the next thing im doing is lowering, body kit, and or new rims for it. but as for speed things i dont know many places that have ZX2 stuff, mainly only fords they have are for mustangs.

[ZedX2]

I haven't had to replace my O2 sensor yet, but I remember on another car I had in the past, the O2 sensor went, and I wasn't planning on keeping the car, so I didn't change it. After a few months, the car ran like crap, and my cat. converter rotted out. What I didn't know at the time was that with a bad O2 sensor, the computer gets readings it doesn't like, and compensates. This can mean adding fuel when it's not needed, or cutting back on fuel when fuel is needed, etc... There's actually nothing wrong with the way the engine is running, but the computer changes things based on the readings from the faulty O2 sensor, and the engine starts running poorly. And in my case, the resulting change in emissions rotted my converter. I can't say for sure that this is your problem, but if your computer is getting a bad signal from you O2 sensor, it might be the problem.

Now a more obvious thing to consider is the plugs/wires. I'm sure you've done that already, but really bad plugs/wires will also trigger the check engine light, and cause stuttering.

Oh...and maybe I'm just old, but don't just make it "louder". Loud exhaust is retarded. A nice deep throaty exhaust that you only hear under hard acceleration...that's nice. Those ricer-burners you hear from 5 miles away while they're only doing 5 MPH...that's just stupid.

[inlinedude2]

ya i did do the wires, it fixed it some, apparently had a bad 4th. but my friend wants to knock it out so it will make it better sounding, now its only heard if i floor it, which is ok but i still want it to be louder than that. only 2-3 miles away is fine by me. but the reason i asked is b/c the stupid sensor is like $100 from the store, and if i knock out the cat it would read anyway, or also the cat could be bad by now idk.