300000 and counting

hello my 1990 toyota pickup truck 4x4 sr5 3.0l has been a great truck, but it has 300.000 miles on it, so first i got a code 52 so i change the knock censer all gaskets, this all started when i rain it to the bone gas empty, so i just know put new fuel filter new gas regulator, after that new codes came up, but not knock censer, but codes 25-26-41, now i just put a new tps and big idle surge came up, im trying to adjust it,but it just not getting there, my truck has been down sence april 2018 because with the check engine light on you know there not going to pass you,spent lots of cash, need some ideas thanks. kevin