1995 Subaru Legacy Hesitant Engine

This problem began about a week ago.I have always had the check engine light on and every time I was told its nothing tooo serious but mainly emissions problem with the catalytic converter. I stopped paying attention months ago. So recently, while driving the car would accelerate ok, drive ok but when you ease off on the gas or are accelerating gently under 2500 rpm, the car stutter's and becomes a bit hesitant. Even on the highway while doing 60-ish, when you let go off the gas lightly, it would stutter.
Now, I waited till my gas was below E and filled up with a higher octane, replaced filter (it was dirty) and used lucas fuel cleaner, nothing. BUT, the check engine light disappeared.
I drained the coolant and flushed it. Nothing.
Done the oil change about 500 miles ago and air filter about 4000 miles ago.
Replaced the pcv valve a few days ago. Nothing

I barely drive it.I work from home.

What could be the problem? It still stutters and hesitant. Any suggestions?