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Symptoms · 3.5 EcoBoost (gas)

3.5 EcoBoost (gas): misfire, rough idle, hesitation or surging

5 documented failures on this engine list this among their signs. They are ordered from the most widespread down. Each one shows the signs in its record's own words, how to tell it from the others, the usual fix and any recall or bulletin.

Charge-air-cooler condensation: boost shudder / hesitation in humid weather Very common · 169 complaints
Cam phaser / VCT rattle and cam-timing DTCs Very common · 107 complaints · 3 recall/bulletins
Ignition misfires: spark plugs and COP coils Very common · 84 complaints · 3 recall/bulletins
Timing chain stretch / guide wear (Gen1 era) Common · 52 complaints · 2 recall/bulletins
High-pressure fuel pump (GDI) failures Occasional · 1 complaints

Not sure which engine you have, or want the recalls for your exact truck? Check your VIN: it names the engine and lists the campaigns for that model year. Whether a recall is still open on your VIN: nhtsa.gov/recalls.

1 Charge-air-cooler condensation: boost shudder / hesitation in humid weather

aggregated How widespread: Very common 169 NHTSA owner complaints match it, out of 667 checked

How it shows up

brief shudder / bucking under moderate acceleration in humid or rainy weather
hesitation or stumble on tip-in after extended light-throttle cruising
intermittent misfire / limp behavior that clears after the intake dries out

Its other signs

smoke puff or moisture from the exhaust on hard acceleration

How to tell it apart

reproduce on a humid day after light-throttle cruising: sustained moderate load, watch for the characteristic single shudder event
check for stored multi-cylinder misfire DTCs (P0300-P0306) without an ignition or fuel cause
inspect CAC for pooling; verify the deflector position / updated CAC hardware

Usual fix

Ford service direction: relocate the CAC air deflector (or updated CAC assembly) so airflow evaporates pooled condensate; owner practice: periodically run sustained boost to purge the cooler

Root cause, parts and sources →

2 Cam phaser / VCT rattle and cam-timing DTCs

aggregated How widespread: Very common 107 NHTSA owner complaints match it, out of 667 checked

How it shows up

rough or delayed cold start

Its other signs

cold-start rattle or ticking that fades as oil pressure builds
MIL with cam-timing DTCs (P0011/P0015/P0016-P0019/P0021/P0025) or VCT circuit codes (P0365/P0369)
PCM updates required after VCT unit or long-block replacement (per Ford SSM)

How to tell it apart

listen for the cold-start rattle versus a deeper knock; warm-engine repeat check
scan cam-timing and VCT DTCs on both banks; freeze-frame at start
verify oil level/condition and oil-filter type before condemning phasers

Usual fix

phaser / VCT unit replacement with the updated hardware and the PCM calibration update; oil-system service while in there

Recalls and bulletins

21N08 TSB 20-2315 SSM 48055

Root cause, parts and sources →

3 Ignition misfires: spark plugs and COP coils

aggregated How widespread: Very common 84 NHTSA owner complaints match it, out of 667 checked

How it shows up

MIL with misfire DTCs P0300-P0306
rough idle and flashing MIL under load
hard start after misfire events

Its other signs

lack of power on the high-output tune (2019 Limited TSB case)

How to tell it apart

read misfire DTCs and freeze frames; identify the cylinder pattern
swap-test the coil on the misfiring cylinder; inspect the plug for gap/erosion
check for CAC-condensation events (multi-cylinder, humid-weather single event) before condemning ignition parts

Usual fix

full set of plugs (turbo service interval, not the NA interval) plus the failed coil(s); boot/inspect on every cylinder

Recalls and bulletins

SSM 50412 TSB 19-2286 TSB-14-0160

Root cause, parts and sources →

4 Timing chain stretch / guide wear (Gen1 era)

aggregated How widespread: Common 52 NHTSA owner complaints match it, out of 667 checked

How it shows up

progressive rough running as correlation drifts

Its other signs

chain rattle/slapper noise at start-up or under light load
MIL with cam/crank correlation DTCs
metal finding in oil on advanced cases

How to tell it apart

listen for chain slap vs phaser rattle (chain noise tracks rpm, phaser noise is start-up transient)
scan for P0016-family correlation DTCs on both banks
inspect guides/tensioner through the service access before committing to a chain job

Usual fix

timing chain, guides and tensioner replacement with phaser inspection; long block if guide debris advanced

Recalls and bulletins

TSB 17-0026 TSB 16-0027

Root cause, parts and sources →

5 High-pressure fuel pump (GDI) failures

aggregated How widespread: Occasional 1 NHTSA owner complaints match it, out of 667 checked

How it shows up

random misfires / hiccups under acceleration

Its other signs

long crank on start-up
sudden power loss in motion
MIL with fuel-pressure DTCs (P0087 family)

How to tell it apart

log fuel rail pressure desired vs actual on a hot restart and under load
check for P0087/P0088 and for metal on the HPFP follower path (oil analysis)
rule out the in-tank pump and filter before the HPFP

Usual fix

HPFP replacement with the full fuel-contamination procedure (flush/rails/injector inspection) when the pump failed internally

Root cause, parts and sources →

Other symptoms on the 3.5 EcoBoost (gas)

Hard start, long crank or no-start Loss of power, limp mode or derate Losing coolant Overheating or temperature creeping up Oil leak, oil consumption or rising oil level Ticking, knocking, rattle or whine

Everything on the 3.5 EcoBoost (gas)Its recalls and bulletins

Order: how widespread each failure is in its record (near-universal, very common, common, occasional, rare), then the number of NHTSA owner complaints that match its keywords. Complaint counts are keyword matches, not a manual review of each complaint. A symptom listed here means the failure is documented with that sign; it is not a diagnosis of your truck. Tiers: verified, aggregated, contested, data-gap. How we tier and source facts.