i'm cruising onto the freeway and i floor it catch a gap in traffic. i'm expecting a downshift which never comes. in fact, i feel like i'm stuck in fourth gear and the tach's STUCK at 4k rpm with NO accerlation. i mean NO acceleration. it's just sitting there and by the sound of the engine, i think it's the motor's waiting for the auto to do its job but it's not. it's disengaged from whatever gear it was in, but IT WILL NOT ENGAGE THE LOWER GEAR.
so i pull off the freeway and shut down for a few minutes and start up again. i rev the engine in P and in N to make sure the motor's ok. no problem, all the way up to 6k. back onto the freeway. same thing. it gets thru mild acceleration all the way thru first, second, then third? i floor it and i feel it disengage to downshift and again, it never does. now the tach's won't go above 3500. this isn't shifting hesitation either. i must have driven about half a mile like this waiting to see if it would eventually shift into a lower gear. it doesn't.
by now i'm freaked and i pull off the freeway and start heading back home anticipating a dealer visit tomorrow. i'm flooring it every chance i get to make sure it wasn't a freak incident. time and again it refuses to downshift under heavy throttle. then, about three lights later, all is okay again!!!! downshifts fine. accerlation fine. wot fine.
what the hell happened? very disconcerting....

 

wierd

I'd take it in to get the tranny checked out...

 

Sounds like the TCM is not thinking correctly. It's normal to have it do that once in a while, but continuously like what happened to you. See what happens today.

 

I found that my car (updated TCM v1), will not downshift if you bring the power on slowly (sometimes). Stomping it will usually bring a downshift, but I've noticed several times that I was sitting there thinking "when's this pig gonna drop down?". If you can't lift and reapply quick punch of throttle without a downshift, then I suspect its time for the service dept.

 

uugh... nissan service...
hopefully when i get this figured out, it'll take care of my plummeting mileage too.

 

No choice -- Go to the dealer. No accel above 3500 RPM indicates the on board computer is not responding and your machine is in 'limp-in' mode. It probably explains the poor fuel mileage as well. Remember that the computer is considered an emission part that is covered by a longer warranty than 36mo/36,000 mi standard warranty.