MajorVery commonEngine

Subaru WRX: FA20DIT 2.0T Direct Injection Intake Valve Carbon Buildup (VA WRX)

FA20DIT 2.0T Direct Injection Intake Valve Carbon Buildup (VA WRX) is a very common engine fault on the Subaru WRX on the 2014 onward cars, and we rate it major. Putting it right costs $600 to $1,600 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 41 documented faults on the Subaru WRX.

Vehicle: Subaru WRX
Engine: 2.0L
Years: 2014 onward
Fuel: petrol
System: Engine

This page covers the Subaru WRX as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Subaru WRX faults41 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Intake manifold yet. We would rather show none than show a picture of a different part.

What goes wrong

As a direct-injection engine, the FA20DIT does not wash its intake valves with fuel — carbon deposits from crankcase blow-by gases accumulate on the back of the intake valves over time. By approximately 80,000–100,000 km, significant carbon accumulation can restrict intake airflow enough to cause rough idle, hesitation on cold start, power reduction, and increased fuel consumption. Unlike port-injected engines, fuel system additives cannot reach or clean the valves. The accepted remediation is walnut-shell media blasting of the intake ports with the intake manifold removed. This is a known and expected maintenance item for all direct-injection engines including the FA20DIT, and any WRX above 80,000 km without documented intake cleaning should be treated as likely affected.

What you would notice

Rough or lumpy idle, particularly noticeable on cold start
Hesitation or stumble under light throttle opening
Gradual power reduction over time with no fault codes
Slightly increased fuel consumption without other explanation

How to check it

Where to look. Intake ports and back face of intake valves inside the FA20DIT cylinder head

Ask whether an intake valve walnut-blast cleaning has been performed and at what mileage it was last done. Any FA20DIT WRX above 80,000 km without documented intake cleaning should be budgeted for this service. If a workshop inspection is possible: If a borescope is available, inspecting the intake ports through the intake manifold will reveal carbon deposit thickness directly.

Parts involved: Intake manifold.

What it costs to put right

$600 to $1,600 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Have the intake valves or intake ports ever been cleaned with walnut blasting?”
“At what mileage was the last intake port cleaning service performed?”
“Has any idle roughness, cold-start stumble, or gradual power reduction been noticed?”

Now check the Subaru WRX you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Subaru WRX buyer questions

Is fa20dit 2.0t direct injection intake valve carbon buildup (va wrx) serious on a Subaru WRX?

We rate it major and very common on the Subaru WRX. As a direct-injection engine, the FA20DIT does not wash its intake valves with fuel — carbon deposits from crankcase blow-by gases accumulate on the back of the intake valves over time. By approximately 80,000–100,000 km, significant carbon accumulation can restrict intake airflow enough to cause rough idle, hesitation on cold start, power reduction, and increased fuel consumption. Unlike port-injected engines, fuel system additives cannot reach or clean the valves. The accepted remediation is walnut-shell media blasting of the intake ports with the intake manifold removed. This is a known and expected maintenance item for all direct-injection engines including the FA20DIT, and any WRX above 80,000 km without documented intake cleaning should be treated as likely affected.

How much does it cost to fix on a Subaru WRX?

$600 to $1,600 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Subaru WRX years are affected?

Our research records this fault on the 2014 onward Subaru WRX. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.