F150 4.2 engine problem...

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F150 4.2 engine problem...
jmn444 avatar
jmn444
+1y
I'm pissed... ITB's in a few days, and my engine starts missing a beat now.... i already did plugs and wires but didn't change how it's acting... anybody have any ideas??? at idle the engine shakes and sputters, it clears out a little when revved, but still a little fuked...
stockflooredsdime avatar
stockflooredsdime
+1y
You might want to try the cap & rotor.

If that doesnt work, try pulling each spark plug one by one (make sure to put each one back before moving to the other).

If its mis-firing you should be able to tell which one it is.
jmn444 avatar
jmn444
+1y
it doesn't have a cap and rotor, has the coil pack deally... can those go partially bad like a cap and rotor would? all the old plugs looked identical when I changed them out... damn this sucks...
FndOnRdDraggin avatar
FndOnRdDraggin
+1y
You either have a bad Idle air control module or DPFE sensor. I work for a Ford dealership I see it all the time. If neither one of those fix it, your probably looking at replacing a fuel injector.
jmn444 avatar
jmn444
+1y
what's the DPFE sensor?
FndOnRdDraggin avatar
FndOnRdDraggin
+1y
It reads your fuel and exhaust, Dual Pressure Feedback Exhaust, it has one line that goes into your EGR valve tube, and one line that goes into the manifold.
jmn444 avatar
jmn444
+1y
ok, will that dpfe cause rough running even at higher rpms? i'm pretty sure its not the iac since its not just at idle... it worse at idle, but still rough at all times...
layingnutz avatar
layingnutz
+1y
I HAD ONE AT WORK THAT WAS DOING THE SAME THING. DID PLUGS AND WIRES AND NOTHING HELPED IT. THOSE ENGINES ARE WORTHLESS. IT ENDED UP BEING THE COIL PACK. CHANGE THAT OUT AND YOU SHOULD BE GOOD TO GO.
jmn444 avatar
jmn444
+1y
any other ideas i can try tonight? is it possible for the coil pack to be bad and still have the truck running? I kinda thought they were all or nothing...
bodydropped85 avatar
bodydropped85
+1y
hmm. any check engine light? if the DPFE sensor is the cast aluminum, it needs to be changed, ford came out with an updated one that is plastic. IAC could be the culprit, also intake gaskets worst case scenario