Strange shake

Hi all,

I have a 1995 legacy L manual AWD. I love this baby ! But recently she began to show some weird symptoms.
Basically, when I am in low RPM, low gear and accelerate slowly, she shakes back and forth a couple of times (somewhat noticeable) and goes back to normal. She does the same thing when I decellerate (by removing my foot from the gas pedal) too. I checked the RPM gauge during this phenomenon and did not see any unusual change. It does not matter if the engine is warm or cold.

Another way of explaining the feeling is like she having automatic transmission and changing gears (you know that slight feeling).

Any help ?

Front end alignement