Toyota Corolla 1995 Stalling Problem

Toyota Corolla 1995auto (1498cc / 5A-FE ) - Stalling problem
We have this car in England which is unusual but more common in USA.
At present the car runs fine from cold always starting first time . Once warm it tends to stall .. this can be after a mile or 10 or more it will then refuse to start again and has to be left for 2/3 hours before it will start , run for a bit and then stall again . Tendency for these stalls when car going uphill . Main dealer has since serviced car but problem didn't happen to them so couldn't diagnose . Now spent 6 weeks at Japanese car specialist who have replaced idle stabilser valve and MAP sensor ,problem still not solved . We have car back and I have cleaned all electrical connectors with switch clean . Rotor and cap seem ok but have also been cleaned also throttle housing and spark plugs seem normal colour of light grey , appear to be no vacuum leaks on pipes etc. car is low mileage 70k miles . Any of you guys got any ideas .. appears to be beyond English mechanics !!!