I’m having an issue with the cruise control in our 09 Murano LE with 126,000 miles. Periodically it does not maintain speed when going up hills while travelling on highways. This includes long low grade hills. It is gradual decrease in speed loosing up to 5 or 6 MPH by the time we start to level out. Speedometer and GPS match and the tachometer is holding steady with a slight drop as the vehicle slows.
I think this may possibly be heat related. Most of the trips we make are 180 mile round trip visiting family by mostly highways. When we start out the cruise control works really well. But depending on the temperature the cruise control varies when it starts acting up. We live around the Philadelphia area. During the summer I could get anywhere between 15 to 45 minutes before it started and it still didn’t function properly on the return trip. But in the winter I can get the entire trip out without problems and sometimes the return trip back without problems if we stayed out there for several hours.
The engine is running well and there are no codes. When it slows down I can lightly apply my foot to the accelerator and bring back up to speed. Also there are no power issues when driving without the cruise control. The air cleaner is new and I cleaned the throttle body and sprayed the MAF sensor with MAF cleaner. Still have the original plugs.

Get the CVT-A and CVT-B signatures on your trans checked. Those are the overheat flags for the tranny, both should be zero. If either one is above zero then the CVT is probably going into self-protection. If you've never serviced the trans then your fluid will be completely shot at 126K, get it changed quickly or future damage is pretty much guaranteed.

Thanks for the reply. I will get this into the shop to have the CVT serviced and looked into the A and B signatures you mentioned. There currently is no noticeable issues with the CVT other than the slight hesitation it always had when shifting from neutral into gear. This was present since it was new and I was told that is normal for a CVT.
I never thought it was a CVT issue since it drove like normal without the cruise control. But that would explain the heat factor.