This is growing to be a horrible frustration of mine, My zx runs great in general, just replaced 2 injectors and cleaned the plenum, but when driving along at about 1500 to 3000 rpm the car has a weird sort of stutter, when i floor the gas the stutter becomes way more noticable, i have been trying to figure this out for a while and i have been cleaning electrical connections for a while and even had a visit to the hospital in my attampts to resolve the problem. Please help. Feel free to ask any questions about the problem to try and pinpoint the problem.
The rpms rise when i floor it like they should, its just that around 2200 rpms the engine sort of hesitates, also sometimes the rpm band in which the problem occurs changes sometimes the stutter will not go away until around 3000 somtimes it stutter s until 4000, its very weird
Jack Of All Trades
It's a rather common problem here. 

F5 Hero
Make sure your fuel pump relay is plugged in good. It's located under your driver side kick panel. Look on twinturbo.net under their faq for changing your fuel filter and it will show you exactly where it's at.
Über User
i had a problem like that...one of my cylinders stopped firing...i found out which one and replaced the coilpack also cleaning the electronics under the floor panel in the car, that solved it....it started out like your problem though and then the coil would kcik in after a certain rpm, but would usually stay working then. my dads car did that, my friends car did that. carbon build up in the intake manifold. or wierd fuel mixture, or the electrical like i said. those are my guesses.
Registered User
i had a similar problem last year when releasing the clutch, i believe it was clutch related or some other drivetrain problem. your problem sounds different though
Registered User
I had a very similer if not identical issue about 7 months ago. The car would idle a little rough (more vibration than normal and not as smooth), hesitate when I gave it some gas froma dead stop and if I let it idle in Drive on a flat surface it would jerk itself along. Classic crappy injector issue. Replaced the one bad one and everyting smoothed out. You've already replaced 2, is it possible you have had another crap out on ya?