r/FocusST • u/FirstDragonfruit3022 • 2d ago
👋 HI, I'M NEW! 2013 st
Just bought my first ST. New engine but it shuts down when I come to a stop or if I’m turning and leaving it in neutral. Fuel pump or vacuum leach? I did get a code for overboost. It never has gone to limp mode. Any help would be greatly appreciated.
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u/bchiodini 2016 ST3 FBO BNR ST67 JST Tuned 1d ago
What is the exact DTC? Any mods to the car? Is it tuned? Mileage?
Check to see if there are any open recalls.
There was a recall (14S17) for wiring harness problems for the PFLs. The problems that 14S17 fixed seem similar to what you are seeing.
Recall 18S32/26S40 were for purge valve problems. If 18S32 was not done, take it in. 26S40 is not a replacement for 18S32. If 18S32 is done correctly, 26S40 should not be needed.
An over-boost problem is probably not a fuel pump issue. If vacuum is not present at the turbo bypass solenoid, an over-boost condition could occur. Check the vacuum line between the turbo bypass solenoid valve and the vacuum pump. They have been known to crack at the vacuum pump fitting (top of the valve cover). Also, check the vacuum line to the BPV or BOV (if you have an aftermarket). It's behind the right wheel.
If you have an aftermarket BOV, it may need to be cleaned and oiled.
If all of the above checks out, it can't hurt to replace the purge valve. If it's defective, stalling and poor idle can occur, especially with a full gas tank.