Hey everyone
Been having this nightmare for a couple months now.

The symptom is that my car feels like its being completely held back.

DSM link shows the engine is running fine during this "hesitation".

I had a similar problem over a year ago and it was my rear calipers sticking.
I replaced those at that time cuz i noticed my rear rotors were getting warm.
The new calipers fixed that problem.

Little after that noticed my master cylinder was leaking, replaced that and car was good.

This winter is when I started having my recent problem. Same symptoms that the car felt held back, AND now my rear brakes were engaging before my fronts.
So I changed my proportioning valve and rear calipers again, and didnt fix nothing.

Thought it was my cat converter, so i changed my exhasut with another one i have, same thing.

I can put my car up so no tires are on the ground and everything spins freely.
(checked this cuz I also put a 4 bolt rear end in with a 22 spline tcase/tranny.
I dont know if this makes a difference but it came out of a 23 splined car? To my understanding the ratios are the same? or are they not? car was fine for a couple months after this swap.

Idling, my car has about 18 or so for vacuum.. When i pump my brakes on idle, they get super stiff, vaccumm goes to 10 and sometimes lower, and car starts to suffer and want to die. after driving for a bit my pedal also feels hard. I changed my vaccuum valve between IM and the booster, even tho i tested the old one and it seemed fine, changed it, still same thing.

To test my booster, I pumped my brakes with the car OFF, till they got rock hard, and pushed while i started the car.. the pedal slowly went down with ease but no where near the floor.

Driver side front and passenger rear rotors also get real warm sometimes, without applying the brakes.... Id downshift and pull over and feel the rotors.

I also did not drain my booster when I had a leaking master cylinder...
and at cruising speed, my car use to have vaccuum of about 15, now its at 10 on cruise load... 22 on decel while in gear..
Could my booster be bad even though it shows signs of being good? could it cause that section of brakes to stay on?
The MC's were identical when i swapped them, its a reman. from part source.. could it be for a 91-94? my car is a 90.. they looked the same like i said.. is there a difference at all?
Need help before this DSM goes down in flames! lol

Thanks in advance!