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  3. HITACHI AUTOMOTIVE SX-0045

HITACHI AUTOMOTIVE SX-0045 Fuel Injection Throttle Body Air 4.2L L6 Ui

fits model: Envoy. make: Gmc. year: 2003–2006.

Sx-0045 Hitachi Automotive Fuel Injection Throttle Body For 2003-2006 Gmc Envoy Xl 4.2l L6 Air Ui

( Brand: Hitachi Automotive ), ( Manufacturer Part Number: SX-0045 ), ( Type: Fuel Injection Throttle Body ), ( Item Weight: 2.8000 ), ( Manufacturer Warranty: 1 Year ), ( Item Width: 5.350 ), ( Item Height: 3.750 ), ( Item Length: 6.550 ), ( Ipn: C482 20-64 ), ( Placement On Vehicle: Air Fuel Delivery Fuel Injection System ), ( Compatible Model: Envoy Xl ), ( Compatible Year: 2006 2005 2004 2003 ), ( Core Charge: Free No Core Charge ), ( Fitment Type: Direct Replacement ), ( Bundle Description: 1 Pc Genuine Hitachi Fuel Injection Throttle Body )

Review HITACHI AUTOMOTIVE Fuel Injection Throttle Body Gmc Xl 4.2l L6 Air Ui fits ENVOY 2003–2006

The **Hitachi SX-0045 Fuel Injection Throttle Body** is a high-performance, direct-fit replacement designed specifically for the **2003 2006 GMC Envoy XL** equipped with the **4.2L L6 (LF7) air injection-equipped engine**. Engineered to meet or exceed OEM specifications, this throttle body is crafted from durable materials to ensure long-lasting performance and reliability under demanding driving conditions. The unit features a **precision-machined throttle plate assembly**, allowing for smooth and responsive throttle operation while maintaining optimal airflow for efficient engine performance. Its **sealed, corrosion-resistant construction** protects against moisture, debris, and wear, making it ideal for both street and light off-road applications. The throttle body is compatible with the vehicle s **air injection system (AUI)**, ensuring proper integration with the engine s emissions and performance requirements. Whether you re restoring a classic GMC or upgrading an existing system, this Hitachi throttle body delivers a seamless fit, improved throttle response, and enhanced engine efficiency, helping to restore or maintain the original power and drivability of your 4.2L L6-powered Envoy XL.

### **Pros and Cons of Buying a Hitachi SX-0045 Fuel Injection Throttle Body for a 2003-2006 GMC Envoy XL (4.2L L6, Air UI)**

#### **Pros:**

1. **Improved Performance** The SX-0045 is a high-flow throttle body designed to enhance airflow into the engine, which can lead to better throttle response, smoother acceleration, and increased horsepower, especially in naturally aspirated applications like the 4.2L L6.

2. **Better Fuel Economy (Under Some Conditions)** In some cases, a high-flow throttle body can optimize fuel-air mixture, potentially improving efficiency if the engine is running leaner or if the original throttle body was restricting airflow.

3. **Easier Installation** The SX-0045 is a direct replacement for the stock throttle body, meaning no major modifications are required. It simply bolts in, making it a straightforward upgrade for DIYers.

4. **Compatibility with Performance Mods** If you plan to add a turbocharger, supercharger, or other forced induction later, a high-flow throttle body can help prevent airflow bottlenecks.

5. **Potential for Reduced Harsh Idling** Some users report smoother idle characteristics after installation, though this depends on the rest of the engine s condition.

6. **Aftermarket Support** Hitachi is a well-known brand in performance automotive parts, and the SX-0045 has a track record of reliability in similar applications.

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#### **Cons:**

1. **May Not Provide Significant Gains on Its Own** The 4.2L L6 in the GMC Envoy XL is not a high-performance engine, and without supporting mods (tune, intake, exhaust, or fuel system upgrades), the benefits may be minimal. Expect noticeable improvements only if the engine was previously restricted by the stock throttle body.

2. **Requires a Tune for Optimal Performance** A stock ECU may not properly map for the increased airflow, leading to rough running, stalling, or even engine damage if the fuel delivery cannot keep up. A custom tune (preferably from a professional) is highly recommended.

3. **Potential for Rough Idling or Stalling** If the throttle body is not properly matched to the rest of the engine s components (e.g., weak fuel injectors, worn spark plugs, or vacuum leaks), it can cause drivability issues.

4. **Cost of Supporting Mods** While the throttle body itself is relatively affordable, upgrading the fuel system (injectors, fuel pump, fuel rail), intake, or exhaust to fully realize the benefits can add significant cost.

5. **Warranty Concerns** If the vehicle is under warranty, installing an aftermarket throttle body may void certain coverage, especially if it s not factory-approved.

6. **Durability Questions** While Hitachi parts are generally durable, the SX-0045 is not built for extreme forced induction. In a naturally aspirated application like this, it should last, but long-term reliability depends on maintenance and driving conditions.

7. **Possible Backfire Risk** If the throttle body is too large for the stock fuel system, it can cause lean conditions, leading to backfires or detonation, particularly under load.

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### **Conclusion:**

The **Hitachi SX-0045 throttle body is a viable upgrade for a 2003-2006 GMC Envoy XL s 4.2L L6 engine**, but its effectiveness depends heavily on whether you pair it with the necessary supporting modifications. If you re looking for a simple, bolt-on improvement with minimal effort, the gains may be modest. However, if you re planning a more comprehensive performance build (including a tune, fuel system upgrades, and possibly an intake or exhaust), the SX-0045 can be a worthwhile investment to unlock better airflow and throttle response.

**For a stock or lightly modified engine, the benefits may not justify the cost unless you re experiencing noticeable airflow restrictions.** If you re already planning other mods, the throttle body upgrade can be a logical next step but always ensure it s paired with a proper tune to avoid drivability issues.

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### **Recommendation:**

- **If your primary goal is better throttle response and airflow without major modifications**, the SX-0045 is worth considering, but expect modest gains unless the stock throttle body was severely restricting performance.

- **If you re building the engine for better performance**, install the SX-0045 **alongside a custom tune, upgraded fuel injectors, and a high-flow intake** to maximize benefits.

- **Avoid installing it without a tune** this can lead to rough running, stalling, or even engine damage due to improper fuel delivery.

- **Check for leaks or vacuum issues** before and after installation, as these can exacerbate throttle body problems.

- **Consider alternatives** like a high-flow intake or a performance throttle body from another brand (e.g., Holley or Edelbrock) if you want more airflow options.

**Final Verdict:** The Hitachi SX-0045 is a solid choice for those looking to improve airflow in their 4.2L L6 GMC Envoy, but it s most effective as part of a broader performance upgrade rather than a standalone fix.

Details:

Hitachi Fuel Injection Throttle Body for 2003 - 2006 GMC Envoy XL 4.2L L6 Air ui: Status: In Stock.

part #: sx0045 price

  • $225.74

specifications carfuelinjector:

  • for models: Envoy
  • for makes: Gmc
  • for years: 2003-2006
  • brand: Hitachi Automotive
  • mpn: Sx-0045
  • type: Fuel Injection Throttle Body
  • item weight: 2.8000
  • manufacturer warranty: 1 Year
  • item width: 5.350
  • item height: 3.750
  • item length: 6.550
  • ipn: C482 20-64
  • placement on vehicle: Air Fuel Delivery Fuel Injection System
  • compatible model: Envoy Xl
  • compatible year: 2006 2005 2004 2003
  • core charge: Free No Core Charge
  • fitment type: Direct Replacement
  • bundle description: 1 Pc Genuine Hitachi Fuel Injection Throttle Body

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  • condition: New
  • Air Fuel Delivery > Fuel Injection Parts > Fuel Injectors

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  • options: Ship-to-home
  • availability: In Stock
  • started: May 3, 2026
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  • # reviews: 652669
  • city: Indianapolis, Indiana
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for models: envoy, for makes: gmc, for years: 2003-2006, type: fuel injection throttle body, item weight: 2.8000, manufacturer warranty: 1 year, item width: 5.350, item height: 3.750, item length: 6.550, placement on vehicle: air fuel delivery fuel injection system, compatible model: envoy xl, compatible year: 2006 2005 2004 2003, core charge: free no core charge, fitment type: direct replacement, bundle description: 1 pc genuine hitachi fuel injection throttle body,
category: auto parts > air fuel delivery > fuel injection parts > fuel injectors, sku: 16253395087682892,
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