Engine misfire on cylinders 1&2

[My5thsubie12]

Anyone please help im at wits end with this subaru its the 1st subaru that I have ever had any trouble with. We bouth the car and it was sitting for a year, my grandfather put new 91 octane in it with the 1/8 tank of old fuel. I told him not too but he is stubborn. The car never has run great one day and every since its been horrible. I have to have transportation to ER(work). CEL is on for misfire in cylinder 1 and 2

We pulled plugs checked compression= all cylinders above 180psi = good
Changed out plugs
Replaced all the vacume lines
Replaced the ECU
Ran sea foam in full tank 0f 91 octane
Even had a subaru technician some out and he ran subaru engine cleaner, adjusted all the idle controls and hooked it to a computer.
I was running sooo smooth and great
Today we unhooked battery to replacxe wiring for the altenator, after starting it up its back to the same issues and now its sounds like its back firing only under load and going uphill. Ive about had it... I still love Subarus but Ive about to be drained dry with this one.

If anyone has any suggestions please let me know I would appriciate it greatly Thanks!
_Tyler