2006 ford e-250 5.4 stalling at stop is the issue MAF Reads good .8v at idle 5.5 GPS fuel trims start off normal but as engine runs short terms go +30% both banks, with throttle increased fuel trims go down to a total of near 0% 02 sensors fluctuate from rich to lean upstream and down stream both banks even after the converters are warmed up.(I’m thinking down streams may not stabilize because of converter efficiency 300k miles on it). I’ve check vacuum lines and pcv connections for vacuum leaks and haven’t found any. Possibly the intake manifold? Need some help with this one anything is appreciated thank you.

 

Hi Shad,

Something you might try, since we need to eliminate it as a possibility.
When approaching a stop, if vehicle is auto trans, place the gear selector in neutral and see if the stalling stops. If so , we can go looking for a reason the torque converter is not disengaging properly.
Please get back to us and let us know how you make out, thanks.

 

Have you tried disconnecting (not unplugging) the MAF sensor and see if it stalls at stop again even if that puts your van in limp mode.