2003 Nissan Sunny • 4 cylinder FWD Automatic • 95,000 miles

Hi, I have a Nissan Sunny, 2003 model, Gulf Specifications. It has run for around 95000 kms, and around a month back a problem with the gear arose. It is a Automatic gear and when I drive the car, it gets stuck on the first gear i.E. The gear does not shift to the second gear. It does not occur every time but it does take place once a while. I usually resolve it by either halting the car and starting the ignition again or it shifts after a while after decelerating and again accelerating.
I consulted a few garage's and some say to change the gear oil while some say there is a sensor problem.
Could anyone please advice me on this situation as it would be of great help.
Thank You!
March 8, 2011.

Check and test the throttle position and vehicle speed sensor

Mar 8, 2011.
Thanks a lot for the early reply.
Do you have any clue how much would the testing and replacement cost?
Thank You once again!

Mar 9, 2011.
Mr Dheeraj, please contact me because I have the same problem like you. My email address is signorsensitive@hotmail. Com Thanks!

Dec 24, 2011.