1994 Other Nissan Models Car surges and stutters.

The car runs smoothly for around 15 minutes and then starts to stutter. The tachomoter stutters. It jumps up and down around 200. Around the 2000 and 3000 mark on the dial. I have been unable to get the car moving past 40km/h when this happens. Sometimes it does it after driving while other times it does it while starting. I have taken it into a shop and they could not find the problem. I have replaced the Sparkplugs and hoses. Changed the MAF (Mass Air Filter)? And still does the same thing. After changing the MAF it has lasted a little longer, it lasts around 40 minutes before it starts to stutter.

I was told that there might be a leak in an air hose, I found one but still does the same thing.

Another person mentioned it might be the "Ignition coil", or a "Distributer Photo Sensor".

If anyone can help me solve this problem it would be greatly appreciated.