Wierd problem in 88 GT

[Old Guy with 87 GT]

sounds like it could be a problem with the fuel pump or the pip signal that activates fuel pump at start up

when you turn on the key the fuel pump comes on for a couple of seconds ....but it won't come on after that till the ecu recieves a signal from the pip sencor (telling it the engine is turning over)

could be a short ,could be a problem with the voltage regulator interfering with the ecu on start up ,could be problem with the fuel pump relay, could be a pip signal problem ,could be a problem with the ecu harness or the ignition switch

get a volt meter and do some investagating in that area(fuel pump relay) check and see when and if fuel pump is coming on ,then check to see how many amps the fuel pump is drawing .......sounds like it could be a pain in the butte problem ,just a matter of eliminating things one by one that can caus problems

hope i helped