04/06/2026
2008 Ford Expedition 5.4L came in with a complaint of “lack of power and can’t go above 70km/hr”.
Test driving confirmed the complaint and I immediately knew the problem. Live data and scanning from the Autel - North America scanner provided further proof of my diagnosis.
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Once back in the shop, I undid the exhaust system and scoped it with the borescope camera, it confirmed I was right, bank 1 converter was clogged up and I removed the bank 2 converter completely to find it clogged as well due to failing internally, just as I suspected.
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When this happens, it chokes up the exhaust system flow and causes extreme cases of back pressure onto the engine along with causing oxygen sensor issues due to the lack of flow.
Robbing the engine of power and causing all sorts of issues.
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Old converters were removed and I welded in a set of high flow converters and did another test drive, everything was back to normal.