[1rugger3]

Really need help here i have changed out my spark plugs to motorcraft oem plugs with .52 gap. Also i have the following codes P0300, P0302, P0303. I am really running out of ideas and need help.

 

[6stang02]

When you changed the plugs did you also replace the coil boots? P0300 should be random misfire detected and p0302 is misfire on cylinder 2 and p0303 is misfire on cylinder 3 I believe. Take one of the coils off and inspect the boot by pinching them and checking for cracks. If there are cracks then replace the boots. Get all of them. If there are no cracks then id recommend looking into a new set of coils. Preferably aftermarket, like msd or accel.

 

[SoCal2V]

Take the coils from # 2 and 3, swap them to somewhere else. Reset the check engine light, wait for it to come back and see if the misfire moved to the corresponding locations you moved the 2 & 3 coils to. If so, you have just confirmed which coils need to be replaced. If the misfire remains at #'s 2 and 3, post back and we will keep going.

FWIW, I am unaware of any aftermarket "performance" coils that offer the same reliability as oem or that deliver on their promise of increased performance.

 

[1rugger3]

changed the coil packs around and so far no misfire code but the really rough idle and back firing with a loud pop under load is still there.