I had the transmission replaced in 2011 on my 2009 nissan maxima because it wouldn't accelerate, even when the gas pedal was mashed down. This issue seems to happen when I'm traveling at a high rate of speed but say I'm going 80 mph, my RPMs jump *** the way up to about 5 or 6 and my car gradually begins to decrease in speed, yet the speedometer will still read that I'm going a higher speed. Like it will say 60, but you can tell it's driving at 20mph. I'll have the gas pedal mashed down and it won't drive. However, if I pull over for 5 or 10 minutes, it will act normal for maybe 10 miles or so, then start up again. Can't figure out what might be causing this. Happened last night, woke up and it was fine, but it always happens when I'm on the highway...at least so far that's been the case. Any ideas?

 

Sounds to me like the CVT is going into limp mode because it is overheating. When it cools off a little its back to normal until it gets hot again, usually caused by high speed spirited driving. You can do a search on this site and find a lot of subject matter about this.

Were there any codes thrown when this happens?

 

Check transmission fluid. It is very sensitive to overfilling or underfilling, either of which will put the transmission into limp mode. Have you tried driving the car in the manual mode where it simulates gears to see if it is stuck in neutral during this occurrence?

 

If you're cruising as 80 or so and you're on a relatively level road you shouldn't have much of a problem however if you're mashing the gas pedal often and/or travel up multiple inclined then you will most likely experience limping of the cvt. Either way I'd say slow it down a bit especially on hot summer days.

 

I have deliberately abused my 2010 CVT until the transmission was whining like the car had a supercharger on it and it never went into limp mode. I tried to make it go into limp mode when I was in Phoenix and it was 115 degrees...couldn't make it after 7 back to back 0-80mph WOT runs. I gave up.

If its going into limp mode that easily, you have trouble with a capital T.