I have an auto '04 350z with 220k miles. Recently, I have been getting the "SLIP" indication while driving at highway speeds, so the car will cut/lose power trying to fix what it perceives as the issue. But, there does not seem to be an actual issue.

This only happens under the following conditions, and I cannot "make" it happen the first time, but can duplicate it after it happens. I hope that makes sense.
- After driving for 5-10 minutes (sometimes it will never happen)
- Decelerating from above 80 MPH, typically without my foot on the accelerator
- Trying to then accelerate or stop deceleration and cruise between 75 MPH and 80 MPH

Once it happens, it will persist until I get home or get to work. It will not happen the next time I get in the car until the above conditions seem to be met. I have never had this happen outside of the above conditions. I can accelerate from roughly 70 MPH after decelerating from 80 MPH and accelerate to above 80 MPH, no issues. I can get down to around 70 MPH and cruise, no issues. I can accelerate from 70 MPH and cruise between 75 MPH and 80 MPH, no issues. I can stop decelerating before I get to 80 MPH and cruise above 80 MPH, no issues. The problem only arise when trying to do something between 75 MPH and 80 MPH.

I do not get the "SLIP" indication when accelerating from any other speed, regardless of how hard I accelerate. Slow, normal, pedal all the way down. Nothing. Every time this has happened so far, it has been a bright sunny day on straight (and flat) South Texas roads.

The "SLIP" indication will not go away until I take my foot off the accelerator and then reapply it. I've watched my speed drop from around 80 MPH to 65 MPH and the indication will not go away until I take my foot off, and then reapply. This wouldn't normally be an issue, but I drive down some FM roads to get to work in the morning (70 MPH limit, only two lanes) and will pass someone and then try to return to normal or have to pass someone else, and the car starts doing this non-sense. Obviously the car is not actually experiencing any slip, does anyone have any ideas what this could be? Bad sensor that needs to warm up before it starts acting up? Something wrong somewhere along the drivetrain? Some electrical gremlin that I will probably never get rid of?

Any help/advice is greatly appreciated. Thank you.

 

My advice is the same as always: pull codes and see what the onboard diagnostic system tells you.

 

I would bet in a faulty wheel speed sensor. But as dkmura said, pull codes and go from there.