I have a 93 Nissan Altima (AT transmission) and while driving my car....sometimes the speed ometer stays on "0" and the RPM goes up while I have my foot on the gas and it sounds like it is stuck in first gear. Then after a minute or so it will shift over and the speed ometer will go to normal and you can hear the gear switch over & the car will also **** a little while it goes into the next gear. Does this sound like it needs a new transmission?

Shear coincidence. You have a transmission problem. Doing 60 MPH your RPM's should be around 2000, Usually a little less. One of you has a heavier foot than the other.

Its a transmission problem check your transmission fluid and any possible vacuum hoses that go from the transmission to the engine.

HERE IS THE ANSWER.
P0725 - Nissan Type Powertrain - Transmission - ISO/SAE Controlled Description Engine speed (RPM) - incorrect voltage signal ECM to TCM
Cause Wiring, RPM sensor, TCM, ECM
P0720 - Nissan Type Powertrain - Transmission - ISO/SAE Controlled Description AT - vehicle speed sensor (VSS)
Cause Wiring, VSS, TCM
P0710 - Nissan Type Powertrain - Transmission - ISO/SAE Controlled Description Transmission fluid temperature sensor - excessively high or low voltage
Cause Wiring, temperature sensor, TCM, ECM
P0826 - Generic Type Powertrain - Transmission - ISO/SAE Controlled Description Up and Down Shift Switch Circuit

the dtcs of your car are so many, my best suggest is go to garage for repair. or if you would like to repair by yourself, you need to buy a diagnostic tool such as multidiag j2534

Could be the speed sensor in the transaxle.

It sounds like the trans is not reaching Overdrive final gear, this is controlled by the computer that shifts the transmission. What needs to be done now to see what is keeping it from shifting into OD is have the Transmission control module (TCM) scanned for fault codes by the dealer or a shop that has the correct electronic scanner for reading the TCM.

Is the car idling high? It sounds like air control valve has gone bad..just a though. I know when a car isn't idling right, its usually that idle air control valve or a vacuum leak

Check the electrical connector for the VSS (Vehicle Speed Sensor). The VSS will be located on the transmission in a spot where the speedo cables used to go. Make sure the connector pins are not corroded or damaged in any way. Check the wiring as well. If OK, the VSS is likely faulty. Check out this link for typical VSS locations: http://www.google.ca/images?hl=en&prmdo=1&biw=1024&bih=653&tbs=isch:1&sa=1&q=vehicle+speed+sensor&aq=f&aqi=g1&aql=&oq=&gs_rfai=

Hi! i have a 2002 nissan altima(3.5 with automatic transmission). i just got the same codes today. i had 2 different nissan technicians check my car. and they told me it's the revolution speed sensor. After 30 min. of use my car revs high until 8,000 rpm and stays on the same gear for a full 5 seconds or more, then changes to the next gear harshly!! sometimes it just won't change gears and i have to stop in the middle of a highway or avenue. lol!!! when i brake to a complete stop, the transmission slips. does this happen to you? good luck, bro!

No....the rpms differ from engine to engine and from manufacturer to manufacturer. RPM's are always higher at higher speeds.

That is normal,If you do the same speed in 4th gear the rpm's will almost double.

The rpm's will repond faster in a manual than an automatic.

In a manual the engine supplies the power required directly to the gear that you have selected thus the engine rpm's will increase or decrease as needed.