Hi, i have a nissan micra 95 automatic and mine was doing exactly the same. I searched everywhere for answers and took it to a garage for a check over. The told me that although it is stiff and difficult to use, there was no aparant problems with the way that it works, everything seemed to be inline! I have also found out that this problem is very common on older automatics and nissans. And was told not to worry......
However...
yesterday i drove out of my driveway and tried to put it into drive, there was a scratch noise and then it wouldnt go into any gear, it was too lose and the car was at a standstill.
After my dad taking long looks at it, we found out that there is a bar joint from the linkage that puts it into gear, this bar had snapped in half.
Please please beware that the same thing could happen to you as i had the same problems as u r expierencing. I advise that you get somebody to locate this "arm bar" on your cars an make sure there is no cracks in it. Otherwise ul b in my situation, trying to find a tiny part for an old car, if i cannot find it then its probably not worth my while keepin the car. If you guys have any other questions, contact me at soniamardel_1987@hotmail.com, the chances are iv expierenced any difficultaies your having, and have learnt a crazy amount about these cars over the past month. Good luck!
sonia, October 2008