I had a similar problem. The car cut out after pulling a hill in warm weather, or would not restart after a brief interval of being parked after fully warming up. Tricky, because without the heatsoak the engine ran perfectly, and so the problem disappeared on all but the hottest days and if the car was parked for more than about 45 minutes. After going through all the FI relay jazz, etc. it turned out in the end to be the hall effect sensor on the distributor. In my case I put off accepting this until too late, when the car died once and for all in the blazing summer heat, 100 miles from home, with wife and 3 year old on board. Rental car, tow fees, repair at an unknown (but honest!) mechanic etc. proved that trying to save money by hoping for a cheap relay cleaning or replacement instead of a rebuilt distributor was ultimately counterproductive.