Q: I drive a 2011 F-150 with the 3.5-liter EcoBoost engine and 26,000 miles. I've been getting a noticeable surge/hesitation on acceleration once in a while. It usually happens when I'm going up hills, and the check engine light just came on the last time it happened. Any ideas before I take it to the dealership?

A: If the problem occurs more often than not in humid/rainy conditions, Ford Technical Service Bulletin 13-8-1 is the latest attempt at a fix. The 3.5-liter EcoBoost six uses direct fuel injection along with twin turbochargers. The hot compressed intake air from the turbos flows through an intercooler to decrease temperature and increase density before the air reaches the throttle body and combustion chambers. Ford refers to the intercooler as a Charge Air Cooler (CAC). The problem seems to be moisture building up inside the CAC. It's believed that in humid conditions, the moisture accumulation reaches a point where water entering the engine with intake air is enough to cause a misfire condition. If your Malfunction Indicator Lamp coming on was the result of one or more misfire diagnostic trouble codes, that's another clue this TSB applies. Ford TSB 13-8-1 is on its fourth revision.

The procedure involves a PCM software update, replacement of the left side catalytic converter, and installation of an air deflector on the CAC. The converter replacement is only performed if there were misfire trouble codes set. This is most likely due to potential converter damage from excessive hydrocarbons in the exhaust, because of the misfiring cylinder(s). The major revision in TSB 13-8-1 is removal of the air deflector installed at the top of the CAC as instructed by TSB 13-3-3. Ford now wants a new style deflector installed at the bottom of the CAC to help reduce the excessive moisture condition. Get it to Ford service and mention the bulletin along with your description of the drivability issues. We hope this is the final fix. Because of the loss of power on acceleration when the problem occurs, the NHTSA has received safety complaints and is currently conducting an investigation. NHTSA Action Number: PE13018 opened May 22, 2013.


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