You need to check/do all of the following... in no particular order. Just do/check all
1. Get a tune
2. Check the fuel pump, might need replacing
3. Clean & check the AFM
4. Get a tune
5. Check for leaky injectors, ensure fuel pressure is correct and so on
6. Get a tune
7. Ensure you have no VAC leaks or tiny splits in hoses.
8. Check/replace plugs correctly gap’d if neccesary
9. Get it onto a dyno, see what the AFR's and similar are doing
10. Check base timing is correct, cam belt/gears are correct.
11. Ensure ALL sensors/plugs/looms are connected properly and perhaps give them all a clean
It's all the basic shit you need to check mate, of which so far you've done none.