I have a problem that seems to be getting worse. When I get on and off the gas the tach jumps a bit and takes a second or so to settle back down. I don't think it's the clutch because there is no slippage and it is fairly new. I'm very easy on clutches (my stock clutch was replaced with a new tranny at 30k and looked to be in great shape).

I've got nismo lsd and JWT clutch and flywheel. One local shop said it is electrical and just a faulty tach but I disagree because I can hear the revs jump in addition to the tach needle.

Anyone have any ideas?

 

Because of the "fly-by-wire" there appears to be a lag between the pedal and RPM response. I also notice that if you are driving and let off the gas the RPM drops some then seems to hold for a second then drops some more. I've had lots of fuel injected cars that did that little trick. I think that's what you're seeing - the normal lag/oveshoot and delay of the system.

 

What I'm seeing is play in the driveline. What you're describing happens when you have the clutch pedal depressed. Mine happens when accelerating. My local dealer said it's normal operation of my nismo lsd but I've had the LSD for two years and the problem just recently surfaced.