96 Stratus poor braking

Problem has gotten worse over time

New Pad/Rotors (2K miles ago), New Rear shoes & cut drums. (100 miles ago)
Bled brakes (gravity bleed)..

Symptom 1: If engine not running pedal is firm, and stops several inches from floor. If engine running (car not moving), pedal travels to floor.

Symptom 2: Eccessive brake pressure required to stop.

Suspect Master Cyl or Pwr brake compent. What's the best way to trouble shoot w/o throwing parts and $$ at it?

If you are suspecting a power assist problem, I would start with the basics. Does your peddle get easier to push while the motor is running? if so then it is working fine as far as power assist. If not then check the vaccum line hooking up to it. However if the peddle responds to the car running, Im thinking that you should get a friend to help you bleed the brakes the right way as I have found the Stratus to not agree with gravity bleeding the way most older cars do. The only other thing I can think of would be to fine-tooth-comb your system while a friend pumps the peddle, as it is a hydraulic system under pressure so the slightest leak will cause undesirable performance. You will need a good light even in the daylight to see all of the places the line runs though. And make sure to inspect your rear wheel cylinders as they tend to let go right around this age in a Stratus and are fairly inexpensive. (I just got a pair for mine at $23 a piece). Other than that, if it all checks out, then your only option would be to throw money at the master cylinder.

Also check to make sure the shoes are adjusted properly.