Flcherokeeguy

I have a 99 grand cherokee 4.0l which ran beautifully until the other day. I got in it to head to work turned it iver and she started up then acted as if it ran out of fuel...i knew i had fuel in tank atleast a 1/4 tank ...but noticed my fuel gauge was reading below E...so i thought i may have been ripped off and someone siphoned my tank. So i went got some fuel... gauge never moved...so i then continued to check pressure at the rail....and got nothing but a dripple. So i grabbed some starting fluid and sprayed down intake and she started right up. So i continued to buy a whole new fuel pump..float switch...sending unit combo and after replacing it i am still not getting anything...new pump wont even turn on with key...could this be bad Ecm???? Please help ive already replaced fuel pump relay and all fuses....i have a 98 cherokee sport 4.0l and was wondering if ecm would be compatable for my 99 grand cherokee...