ok i got the basic civix ex with the basics done to it exhaust and intake and a stage 2 clutch but i am having this problem with it and it started about a month ago. it only did it every now and then but now i cant get it to stop. when i am driving at a steady rpm it feels like i am dropping a cylinder or something give it more gas and it goes away intill im at a steady rpm and does it again. if i turn the car off as im rolling it wil stop for a minute and back to doing it again. i have replaced plugs, wires, cap, rotor, fuel filter, cant figure out what it could be. i hooked up a scanner to it and when it is dropping a cylinder it shows the fuel system is closed so i replaced the fuel pressure regulator and the injectors and fuel rail and still same ****. can someone help if they have ever had this problem

 

check fuel pump

 

My '90 Si exhibited similar symptoms, most obvious at about 25-30mph in 3rd gear. In my case it turned out to be a slow and lazy O2 sensor. Another symptom was if I tried to hold a steady rpm of around 2200 in neutral, the tach would vary roughly 50rpm +/-. Test your O2 sensor before spending $ on a new one. Shutting down and restarting makes the ECU wait a while until it uses the signal from the O2 sensor again. I think this is where you should be focusing your troubleshooting time.

I doubt it's the pump since the trouble goes away when you give it gas. Seems there is enough fuel available.

Another long shot... is you TPS sensor good? It's a variable resisitor and might have a bad spot, but I would put this possiblity at the bottom of your list of things to check.