Escort 1.3 ’92 often goes unmotivated

We have a problem with a 92 Ford Escort 1.3. The car runs out more often, mostly when uncoupled before a crossing, rather when it is warm, outside by 0°. Mostly it starts again without any problems, sometimes it does not start after up to 30 attempts, only after one pushes it from the crossing. If one wants to recreate the problem, the car drives normally without the engine running out at all. We asked the seller and then changed the fuel filter. Sometimes he doesn’t accept the gas when changing gears. Could this be connected somehow? It runs well in a standing position, idling rotation is constant. Temperature and oil are OK. Consumption is normal, 7 – 9l. Spark plugs are almost new, TÜV / AU too. My question to you: What is the easiest or cheapest solution, so that it becomes more reliable? We don’t have a lot of money as students, but time and contacts.