1986 Subaru XT car feels like its dying

So I about 2 weeks ago the temperature gauge in my car was bouncing up and down and the car became really hesitant when it did this the ecs light would come on. So I would completely turn the car off for a sec and back on while driving and it would run fine. Now the second the temp hits normal it pretty much just dies. Feels like its not getting gas. And if I put it in neutral it will stall. Thought it might be the cat. But it wasn't I was also told it might be the engine coolant sensor connection, that it was corroded, but I couldn't find it. So at the moment I cant drive it because 3 miles down the road it will do this. But when I first start the car and the engine hasnt warmed up yet it runs fine. Any help would be great. Btw its the 86 4wd turbo xt gl-10 if that mkes a difference. -Jesse