My 1979 rx7 won’t stay running unless I keep the ignition turned over I’ve replaced the fuel pump and filter and spark plugs any idea on what’s wrong

 

Many times when this happens it's the ignition switch that gets dirty/out of wack. You can take it apart and clean a lube the ball bearing a little. Be causefull when taking it apart. There are a few small ball bearings that can go flying.

 

Same here with my '83. Had to replace the ignition cylinder some time ago. Not fun, but doable.