hesitation/light throttle 50+mph

hi, im experiencing hesitation at light throttle between 50-55mph and sometimes at 45 and ive done the following:

replaced spark plugs and coils with motorcraft

replaced fuel filter

cleaned MAF sensor

took it to a trans expert and he said its not the transmission also got a trans filter and fluid replacement

got a catalytic converter restriction test and it was good

i have a P0420 catalytic efficiency code below threshold bank 2 but its been there way before i started having this problem


any advise? thx in advanced!

Check EGR valve and DPFE sensor. DPFE sensor is located on the very back of the passenger side head. It has an electrical connector and two rubber hoses attached to it. Often water from the exhaust condenses in this and can give false readings. Removing the sensor and smacking it in your hand to get the water out usually helps.

Check the EGR for proper operation by removing the vacuum line from the top of the EGR valve and using the vacuum line from the fuel pressure regulator to apply vacuum to the EGR valve. If the engine gets rough and then compensates for the roughness, it is working. When removing the vacuum, the engine should return to higher RPMs and then compensate to normal once again.