Engine light with no codes.

Recently my timing belt snapped going down the road and bent my valves so i had my valves replaced and heads and gaskets redone.
After getting everything put back together it will not drive down the road correctly. It has a bad miss. But it idles completely fine.
Also my engine light is on but when plugged in it doesnt throw any codes?

Any ideas of what could be wrong?
I was told it could be a sensor or the timing was still off.
But if the timing was off it shouldnt idle right, correct?