P0300 on a 2018 Ford Edge
P0300 is a generic OBD2 powertrain code for random or multiple cylinder misfire. Unlike P0301 through P0308, it does not point to one specific cylinder, so the cause can be ignition, fuel, air, sensor, or mechanical.
Not your vehicle? See general P0300 info.
Most common causes on the 2018 Ford Edge
Ranked from 779 NHTSA owner complaints filed for this vehicle.
- 1
Coolant intrusion into the cylinders from a cracked engine block/head gasket (known 2.0L EcoBoost defect, TSB 19-2208 / 22-2229 / 19-2346)
High severityThe overwhelming majority of owners report coolant leaking into a cylinder (often confirmed by borescope) with no external leak visible, causing white exhaust smoke, rough idle, cylinder-specific misfire codes (P0300-series), and ultimately requiring a full engine or long-block replacement. This is a well-documented design defect on the 2015-2019 2.0L EcoBoost.
Reported in 28 NHTSA complaints - 2
Worn or coolant-fouled spark plugs
Low severityCoolant contamination in the combustion chamber fouls the spark plugs; at least one owner had plugs replaced first (before the coolant intrusion was found) after a rough-idle complaint, and another had plugs replaced twice as symptoms recurred.
Reported in 2 NHTSA complaintsParts:spark plug - 3
Failing ignition coil
Medium severityA weak coil-on-plug unit, sometimes damaged by coolant/oil contamination in the cylinder, drops spark energy to a single cylinder.
Common causeParts:ignition coil - 4
Clogged or leaking fuel injector
Medium severityA dribbling or restricted injector under- or over-fuels a cylinder, producing a steady misfire independent of the coolant-intrusion issue.
Common causeParts:fuel injector - 5
Vacuum or intake/turbo boost leak
Medium severityOn a turbocharged EcoBoost engine, a leaking intake or charge-air hose leans out one or more cylinders, especially noticeable under boost.
Common cause - 6
Low compression from worn rings, valves, or coolant-washed cylinder walls
High severityPersistent coolant intrusion or normal wear can wash oil off the cylinder walls and drop compression on an affected cylinder, worsening the misfire.
Common cause
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These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0300 on your car still needs shop confirmation before any repair.
Common symptoms
- Flashing or steady check engine light
- Rough idle
- Shaking under acceleration
- Loss of power
- Fuel smell from exhaust
What to check before replacing parts
Scan for cylinder-specific misfire codes
Look for: A companion P0301–P0308 pins the misfire to one cylinder — start there. P0300 with no cylinder code points at something hitting several at once: fuel pressure, a large vacuum leak, or timing.
Inspect the spark plugs and coils
Look for: Pull the plugs: black/sooty = rich, oily = oil intrusion, white/blistered = lean or overheating, cracked porcelain or an out-of-spec gap = replace. Then swap a coil to another cylinder — if a cylinder-specific code follows the coil, the coil is bad.
Check fuel trims for a vacuum leak
Look for: High positive short- and long-term trims (worst at idle, improving as RPM rises) mean unmetered air is getting in. Smoke-test the intake and listen for hissing.
Verify fuel pressure
Look for: Compare running/cranking pressure to the vehicle spec. Low or dropping pressure starves multiple cylinders and reads as a random misfire — suspect the pump, filter, or regulator.
Compression / leak-down test if ignition and fuel check out
Look for: A cylinder 15%+ below the others, or leak-down hissing from the intake (intake valve), exhaust (exhaust valve), or oil filler (rings), means the misfire is mechanical — not a swap-in part.
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