SD854runner

So i bought this 4runner about 8 months ago on the test drive and on the drive home (20miles) it ran fine but when i tried to start it up again it had a miss that would go ba ba ba ba then run fine for a few min then do it again. I changed the spark plugs and wires (ngk on both), new coil (MSD blaster), and replaced the O2 sensor (to try and fix the random CEL issue (the light will come on when cruising down the freeway when the throttle is held at a constant position for to long but if i let off the throttle it will go off, also when in gear and decelerating it will flash 3-4 times). By some random happenstance I met the guy who bought the truck off the original owner and he told me that he changed the fuel filter not long ago. I ran Lucas injector cleaner ever other tank for awhile and the miss issue went away but the CEL has continued to do what i have previously stated. Due to the fact that it started running fine and i dont need to smog it for another 2 years i didnt pursue the CEL issue. When i check the code it gives me the one flash all good reading. so fast forward to now. The truck sat for a little over a month and when I started driving it again the misfiring has returned and this time its worse. I have started to run the lucas injector cleaner but this time with no results. I have checked the timing, the AFM with the ohm reader and it all checks out. At this point im not sure what else to do and I dont have the income to just keep replacing parts until it get fixed, Also i checked the Knock sensor and its tight and the connection is good, i checked the ground from the battery and disconected the ground wire on the intake manifold cleaned and sanded both sides to ensure there is not an issue there... If anyone has any idea of what could be causing these issues and if there are ways to test the possible bad parts before i just keep replacing stuff that would be very much appreciated.