Does anyone have any advice/help/similar issues?

So, yesterday i changed my intake manifold
gaskets and throttle body gaskets on my 96
mustang gt (don’t think has anything to do with the
problem, just putting it out there) but after
everything was going smoothly car was running
stronger. but later i go to drive it and while drive it
starts being very hesitant, doesn’t want to
accelerate, cutting in and out, so i try to just hurry
and get where i was going and my rpm and oil
gauge randomly stopped working then my mph
gauge stopped working and i was at a stop sign on
a little hill and put it in 1st and tried taking off and
didn’t even have enough power to catch 1st and go
just kept cutting in and out worse and i couldn’t
move much. then car died in middle of the road at
the stop sign, thought maybe was low of fuel
(wasn’t the issue) , thought maybe battery got
drained, jump started it immediately even with a
bad connection so don’t think it’s battery. thinking
it’s either fuel pump , alternator , bad injector
connection, or something electronical, any advice?