1994 Jeep Cherokee Jeep cuts out after being run for about

Hi it will drive for about 10 mins then won, t start sometimes starts up after a few mins but not before some times will not start at all I looked up this seems to be a common fault but nobodies saying what the problem is according to the mechanic that looked at it he said the fuel system is ok but he couldn, t get it started so he does, nt inspire confidence alot of peple that have had a simular problem have changed the fuel pump on a number of times tono avail some seem to think it is its the ecu but at $600 its a bit steep if it doesn, t work surley with all the faults that are on this car somebody knows what the problem is and what to test first this is a desperate situation as like most people I haven, t a lot of money and need the car can anybody please point me in the right direction and if it is a common fault if you can let me know I would be very gratfull thanks for reading it is apperiated paul