I installed a Apexi RSM(newer) with a g sensor, and a VAFC2 into a vafc jumper harness on my obd2-ver b ecu. When i had them both hooked up on the same harness, the car would redline at 8240 RPM and would feel sluggish and underpowered a bit aswell as the speedometer needle would jump and fall erratically. After i had removed this RSM, the car felt much faster, and the redline went back up to 8400 RPM and no more problems at all.

What is causing this problem, i had this thing hooked up three times so far according to apexis instructions and it never worked properly. Is ther something i am doing wrong?

 

I'm not sure what's wrong, but I usually skip the harnesses and wire directly. Harness usually cause problems for me when it comes to the VAFC. I'm not sure about the RSM though. My friend has both of those on his 00 GSR and redlines at 9300.