[ROM3000]

Hey all. I'm having an issue with my 2013 Focus ST. The car has 76,000 mi and is completely stock other than a catback exhaust. Under light throttle the car hesitates, as if it is misfiring. I have had the wiring splice recall done, and never had any of the issues related to the wiring splice recall before it was performed. Which gear the car is in doesn't matter; however, it only seems to happen between 1,500 and 2,200 rpm. It's intermittent. One day it'll only happen when the engine is cold, the next day it'll be fine and towards the end of my commute when the engine is warm, it'll start to hesitate. Adding throttle always seems to cure it. I have tried replacing all (4) spark plugs, visually inspecting the intake sensor, replacing the air filter, doing a KAM reset, and checking the intake for any visual tears or leaks. The car doesn't throw a code, which leads me to believe it may be an electrical issue. Could it be that the splice is somehow coming undone? Has anyone else had a similar issue and found a way to resolve it? Any help would be appreciated. Thank you.

 

[ST_Fan]

Sounds like bad splices, grounds, or condensation in the IC and charge pipes. Set your plug gaps to .028.

Also check your Active Grill Shutters. Make sure they open and close with the A/C.

Sent from my SM-G930T using Tapatalk

 

[GotAFoSTnSpeed6]

Did this guy ever figure this out cause this is almost to the T what i seem to be expriencing except ive already did plugs and valves and compression tests those are all good

 

[xTheMan42]

Another possibility would be the Wastegate actuator trying to determine how much boost to apply if your throttle is too light, which causes some hesitation.

But that's one of many possibilities. I assume for a KAM reset, you disconnected the ground wire for at least a few minutes?