Yes I know this is for mustangs but its still a modular engine question. So 2004 Expedition, 234,000 miles and the engines never been opened up. Driving along tonight down the highway with cruise on and right before my exit I feel a couple big bucks like the engine lost power and kicked back in. So i think, that was strange, and coast the the stop sign. I get into it a little off the light to see if everything ok, seems fine, then 100yrds later I'm going up a small hill and it bogs like crazy, and just flat out dies. Kept good oil pressure (checked oil to and its fine) and the charging system had juice. It threw a code so ill check that tomorrow, but with a 5.4 with 234,000 what am i looking at most likely, timing chain is my likely guess.