2013 Ford F-150 P0300 and P0306 Misfire under heavy load/acceleration

Question

My 2013 EcoBoost is driving me crazy. It idles fine and cruises okay, but as soon as I try to pass someone on the highway or climb a hill, the whole truck starts shaking and the CEL flashes. It's almost always a cylinder 6 code, but sometimes P0300.

I swapped the coils between 5 and 6 and the misfire stayed on 6. I've heard these engines have issues with moisture in the intercooler, but I'm not sure if that's what is happening here or if I have a bigger mechanical issue. Plugs were done 15k miles ago.

OldSchoolOtto · Answer

✅ Confirmed fix: Drilled a 1/16th inch weep hole in the lowest point of the intercooler (CAC) and replaced all spark plugs with Motorcraft SP-580s gapped to .030. The shudder was caused by condensate ingestion from the intercooler under boost. After the weep hole, the moisture drains out and the misfire is completely gone.

AudiAlex22 · Answer

Check the gap on those plugs again. EcoBoosts are notoriously hard on plugs and they should be gapped to 0.030 or even 0.028. Also, look at the porcelain for carbon tracks. If you see black lines, the spark is jumping the boot.

EuroEricaW · Answer

Might want to look at your high-pressure fuel pump (HPFP). If the pressure drops during high demand, the cylinder furthest from the inlet can lean out first. Check the PID for fuel rail pressure vs desired rail pressure.

2013 Ford F-150 P0300 and P0306 Misfire under heavy load/acceleration

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