Dual Injection Fuel Injector Cost in 2026
Dual-injection engines (Toyota D-4S, Ford Dual Fuel Injection, certain VW/Audi variants) put both port and direct injectors on the same engine. That means twice as many injectors per cylinder, but in practice it does not mean twice the replacement cost because failures usually involve only one side. The cost decision tree is more nuanced than on single-injection engines and the diagnostic step before authorising work matters more.
One side failing (typical)
$500 - $900
4-cyl, port or DI only
Both sides 4-cyl
$1,300 - $2,200
8 injectors total
V6 full both sides
$1,800 - $2,800
12 injectors, rear-bank labor
Why Toyota Built D-4S (and Why It Matters for Cost)
Direct injection has well-known benefits (better efficiency and power) and one well-known drawback (intake valve carbon buildup because fuel never washes the valves). Toyota's solution was to add port injection back into the mix, run port at idle and low load where the cleaning effect matters most, and switch to direct injection at higher loads where efficiency matters most. The D-4S system manages this transition transparently.
For replacement cost, this design produces two distinct failure profiles. Port injectors fail in the classic carbon-clog way over time (often respond to additives and cleaning). Direct injectors fail in the modern electrical or mechanical way (typically require replacement). The smart owner question to ask the shop is: which set has the issue, port or direct?
Replacing only the failing side keeps cost in the $500 to $900 range for a 4-cyl engine. Replacing all eight injectors as a precaution (which some shops will recommend on a high-mileage car) puts you in the $1,300 to $2,200 range. Whether the precautionary approach makes sense depends on the car's age and your plans for keeping it.
D-4S Vehicles and Cost Bands
| Vehicle | Engine | One side | Both sides |
|---|---|---|---|
| Toyota Camry 2018+ | 2.5L A25A-FKS | $500 - $900 | $1,400 - $2,100 |
| Toyota Corolla 2020+ | 2.0L M20A | $550 - $850 | $1,300 - $1,900 |
| Toyota Highlander V6 | 3.5L 2GR-FKS | $900 - $1,400 | $1,800 - $2,800 |
| Subaru BRZ / Toyota 86 | 2.0L FA20D | $700 - $1,000 | $1,500 - $2,100 |
| Lexus IS350 / RX350 | 3.5L 2GR-FKS | $1,000 - $1,500 | $1,900 - $3,000 |
| Ford F-150 5.0L 2018+ | 5.0L Coyote dual | $1,400 - $2,200 | $1,800 - $2,500 |
Triangulated against RepairPal, Mitchell ProDemand labor times, and Toyota and Ford dealer parts pricing as of May 2026.
The D-4S Diagnostic Decision Tree
Step 1: Pull fault codes with a scan tool. P0300 plus specific cylinder codes (P0301 through P0308) is your starting point. P0087 (low fuel rail pressure) specifically points to the direct-injection side, which could be the direct injectors or the high-pressure fuel pump.
Step 2: Symptom timing. Cold-start rough idle that smooths out points to port injection (because port handles cold start). Misfire under high RPM and load points to direct injection (because DI handles high load). This is not a perfect test but it is a meaningful first filter.
Step 3: Per-injector flow balance test. A Toyota dealer with Techstream or a Toyota-specialist independent with a comparable scan tool can run a controlled flow balance test on both port and direct sets, measuring fuel trim per cylinder. This is the definitive diagnostic.
Step 4: If port injectors are confirmed at fault, try cleaning first. Ultrasonic cleaning of the four port injectors runs $50 to $100 per injector and often restores spray pattern. Total: $200 to $400 versus $500 to $900 for replacement. If symptoms persist after cleaning, proceed to replacement.
Step 5: If direct injectors are confirmed at fault, replacement is usually the answer because cleaning is less effective on the high-pressure side. Confirm the high-pressure fuel pump is in spec before authorising the injector replacement.
When to Replace All vs Half
The argument for replacing only the failing side is straightforward: it saves $700 to $1,300 on a 4-cylinder or more on a V6. If the engine has fewer than 100,000 miles and the other side shows healthy fuel-trim values, replacing just the failing side is the rational choice.
The argument for replacing both sides at once: shared labor. If the intake manifold has to come off for direct-injector access, the marginal labor cost to also replace the port injectors is small (maybe 0.5 hours additional). At a 150k+ mile car where both sides are likely degrading, doing both at once means you do not face another major service in 30k miles.
Practical rule of thumb: under 100,000 miles, replace the failing side only. Over 150,000 miles, consider both sides if budget allows. Between 100,000 and 150,000 miles, do the diagnostic and let the data drive the decision.