I have recently bought a 2000 GS-R and have replaced the secondary O2, and map sensors, and put a new fuel filter in the car. The VTEC seleniod is clean and fine. Now for the question/problem...my VTEC kicks in at 4600 RPM's and from 4600-5800 RPM's it boggs down real bad and will only pick up 10-15 MPH in that 1200 RMP range that it boggs down. Once it hits 5900 it picks up it's speed no problem. Why is this? What can I do to fix this problem? Please someone help me!!!

 

well first off if you gain 12mph in 1200rpms....then thats what you were suppose to gain, the transmission still spun to those certain rpms, unless your clutch was slipping but thats doubtful. and the pick up at 58-5900rpm is the secondary butterly system opening up. id say check the timing, but id say the short bog might be normal due to the butterflys.

 

The thing with that is, it never acted like that before. (about a week) But all of a sudden it is not wanting to accelerate as fast.

 

last tune up?

 

I tuned it up the day after it started acting up