Alright, so now I am stumped. I got these codes a few days ago on my brothers car. Switched out the wires and plugs and it went away. Car appeared to be running great. Tonight, my brother informs me that the car got the CEL again, same codes. Took it around the block, and this time the CEL begins to flash. Now I am puzzled. No new codes, SSDD.

Any ideas?