I have this ix MR, Its jdm, And from the beginning there was a problem, there was no acceleration feel whether i'm at boost or before boost, it seemed like it doesnt matter if i push the throttle 100% or 50% there is no increase in acceleration like it should be, its going at a constant pace no acceleration, after i changed my clutch and plug and air filter , nothing improved, all the same but somehow driving the car at a regular basis, it seems i've over come the problem, but just after a cold start when i heat it properly the car performs at 100% performance, before boost at low rpm this car response is very impressive and after boost it pushes you to the seat like hell, too much of force....but after a few hard driving again the performance drops, like no acceleration before and after boost, it seems the performance drops and again rises, and initial lower rpm drive feels heavy and no response doesnt matter if push the throttle by 20% or 40%, acceleration doesnt increase in that way like it does when the performance is 100%... and sometimes when the car is at 100% and i'm driving hard suddenly it drops the acceleration...
Any idea what the problem might be ? Note that my car it totally stock, no exhaust but i removed the cat with a test pipe...and just a ralliart drop in.
Please help anyone, i will mean a lot....
Please help....

 

Is the check engine light on? Have you checked for any codes?

 

yes, no code and no check light....
it seems like the car is having a hard time to pace up the acceleration and feels like the acceleration is heavy, doesnt accelerate all through the rpm like it should....
Any idea what it could be? Feels like the car is struggling and having a hard time to go up with the acceleration :/

 

You probably need a tune. What it sounds like is you are getting knock and its pulling timing. If you get enough knock it will reduce you to the low octane maps which probably run like ****.

 

Yea id go get a tune if you havent already

 

+3 on tune, check fuel pump or injectors. Could be getting lack of fuel if fuel pump is going out or if a injector is a bad