Flashing check engine light?

[bubbs16]

my truck was doing this last summer. I had a bunch of things done but only 1 thing fixed it. List of things i had done

Air Filter
Fuel Filter
Spark Plugs
Oil Change

I would never do a tranny flush have always heard bad things about the flushing part from a tranny guy i knew. I got mine drained and they added that instant shudder fix with new oil. That was the key fixed it immediately.

Also i did have some water in my coil plugs once from the dealership washing the engine bay with a powerwasher. That engine cannot take that, the water gets in those coilplugs. You can take them off pretty easy and spray some stuff down there and let them dry out.I think its di electric grease you can use.