No power / fuel pressure ??s
 

I am trying to resurrect a '85 GSL-SE. I bought it about a year ago non-running but was told she just stopped driving it so no known mechanical issues. ~140K bone stock. Initially when I got it home it fired up on the old nasty gas (I had meant to disable the fuel pump but forgot when I was messing with it.) Drained the old gas and added fresh and it seemed to run and move fine. Fast forward a couple weeks (insurance and tags) now it won't hardly run. It has no power and you have to feather the throttle to get it to rev up. Sometimes it will idle and sometimes as soon as it goes off high idle it just dies. I replaced the fuel filter and external fuel pump. My pressure tester (hooked up in-line) reads around 40 psi with the engine off. Around 32 at idle and drops as low as 22 psi when the RPMs are fluctuating.

It still seems like a fuel issue to me but I am a Mazda / rotary newb. Can anyone verify the fuel pressure going up and down is normal and what else to check?