Nissan Pulsar GA 15 flooding when it gets hot

[waitoa485]

I have a 94 nissan pulsar that i use as a driving school car.whenever it gets hot the revs will come up while its idling and when you press the accelerator it will flood. I don't think that the fan cuts in when it gets hot and it doesn't seem to overheat when i have the air con running. Ive taken it to our local nissan workshop and the replaced the distributor as it came up[ as a fault on their diagnotics computer, but that made no difference. They then reconditioned the air flow meter again to no avail. They have now replaced the temperature sensor for the coolant so i guess i wont find out till next time it dies when I'm in the middle of a driving lesson! How frustrating!