I don't know how simple it is... Ford couldn't put their finger on whether it was the intake manifold or heads. My associate couldn't either. And i definitely can't myself. I've noticed that i can control it though now. I can keep gassing it to keep it alive, but sometimes between having to break and keep the car from not stalling- it'll stall. Also noticed it seems to happen more when engine is hot, not as much when cold or has AC on. But yeah.... I haven't the slightest idea what it is at this point, I have enough time, i'm almost willing to take out the engine and put in a clean one. I've had TWO different sets of gaskets put on, the leak still comes through.