89 trooper keeps quitting

my friend has a 89 trooper 2.6 engine,standard tranny, that will run/idle for about 4 seconds,quit, then run again about for about the same 4 seconds after immediate re-start, has fuel in the rails, spark to the coil, new fuel pump and can hear the pump working, he thinks it has a relay problem to the pump according to the troubleshooting book, I said check to see if you got a grounding problem somewhere in the system, anybody else have any ideas of where to look next? thanks beforehand.

problem solved, was the plug/connector on top of the gas tank to the fuel pump, plastic retaining clip had broke and plug wasn't quite making it to keep running

i had the same problem this winter. my isuzu quit on me in a snow drift. after about 3 days of trying to figure it out i had found the ground had broke on the fuel pump. drilled and tapped the connection, put a machine screw to hold it together and liquid tape for sealant and haven't had a problem since. i first thought it was moisture in my fuel.