Nissan Repair: 97 sentra auto trans doesnt shift gears, hot sunny day, throttle linkage

Question
Hey VON thanks for your expertise and sharing it with us.  Question: Is there something external that assists my Sentra's automatic transmission to shift through its gears automatically?  I.E. a vacuum hose, suction valve, shift controller?  

Background: I have a 97 sentra with 130K miles.  It runs great like a NISSAN is expected accept, I must let off the gas (for a few seconds) to assist/shift the transmission through its gears; from one gear to the next.  Yes, its an automatic but, I have to treat it like a manual trans.  

You see, It'll shift gears automatically BUT, I must excellerate slowly through the 2K and 3K RPM range in order to automatically do this; or, let off the gas pedal for a second or three then ease into the pedal in order to get the next gear going.

NOTE: I changed out the trans fluid... but, no change in shifting.  I also noticed that the few seconds I need to deceleration is less when I drive it around in colder climate; like real late at night or earlier in the morning vrs the HOT sunny day when leaving work.

Any help would be sincerely appreciated...  I took it to a few trans shops but, was told their not sure.  One said, its third gear is bad.  I doubt them all because its trans is great accept I have this problem shifting through all gears.

Again, Thanks!

Bob...

Answer
Bob,

Check the throttle position cable.  Sounds like it is too tight and it is causing really high RPM shifts.  With the engine off have someone press the throttle to the floor.  You, under the hood, look at where the throttle cable is and check out the other cable that is being pulled by the throttle linkage.  Follow that to the transmission and you have found the throttle position cable.  Now, with the car at full throttle check for slack.  The cable should become almost tight at full throttle.  If it is too tight it will cause your problem.  There are two nuts that lock the cable length in place.  Move the nuts to adjust the cable and then tighten them in place.  Drive the car and see how it does.  It might take a couple of times and go slow so as not to get it too far out of adjustment.