Ford Taurus Fuel Injection Plenum Gasket Guide (2014-2019)
Fixing a rough idle or lean codes on your 3.5L V6 Taurus often points to a leaking plenum gasket.
- The most common sign of failure is a Check Engine Light with lean codes P0171 and P0174.
- It is critical to replace both the upper (plenum) and lower intake gaskets at the same time for a complete repair.
- Quality aftermarket brands like Fel-Pro are reliable alternatives to OEM parts; budget brands are available but may compromise longevity.
- This is a manageable DIY job for an experienced mechanic, but requires a torque wrench and careful reassembly.
Is Your Taurus Running Rough? It Could Be the Intake Gaskets.
If your 2014-2019 Ford Taurus is idling poorly, hesitating when you accelerate, or has the Check Engine Light on, a failing intake manifold gasket is a common suspect. These gaskets are typically made of molded rubber and are subjected to constant heat cycles from the engine. Over time, they can become hard, brittle, and compressed, losing their ability to seal properly. This leads to vacuum leaks, which are the most frequent cause of failure for this part.
Check Engine Light Codes: P0171 and P0174
The most common sign of a leaking plenum or intake gasket is the illumination of the Check Engine Light with diagnostic trouble codes P0171 (System Too Lean Bank 1) and P0174 (System Too Lean Bank 2). These codes mean the engine's computer is detecting too much oxygen in the exhaust, typically caused by unmetered air entering the engine through a leak. While other issues like a dirty MAF sensor can cause these codes, a failed gasket is a primary culprit.
Choosing the Right Aftermarket Gasket Set
You do not need to buy parts from the dealership for this repair. High-quality aftermarket gaskets are widely available and often provide a reliable seal. However, quality can vary between brands.
- Premium Aftermarket (e.g., Fel-Pro, Victor Reinz): These brands are well-regarded in the repair industry. They often design their gaskets specifically for the repair environment, sometimes with improvements over the original factory design to help seal imperfect surfaces. They are a trusted choice for reliability.
- Budget-Friendly Aftermarket (e.g., Skyward, SKP, Store Brands): Brands like Skyward offer a more affordable option. These parts are typically sourced from overseas manufacturers and serve the budget-conscious DIY market. While they can provide a functional seal, especially for a simple rubber gasket, their longevity and material quality may not match that of premium brands or OEM parts. For a critical seal, weighing the cost savings against the risk of having to do the labor-intensive job a second time is important.
Pro Tip: Replace Upper and Lower Gaskets Together
The 3.5L V6 in your Taurus has an upper intake manifold (plenum) and a lower intake manifold. To replace the six lower intake gaskets, the upper plenum must be removed first. Because of this, it is standard practice and highly recommended to replace the upper plenum gasket at the same time you replace the lower gaskets. Most aftermarket kits are sold as a complete set for this reason.
Known Issues, Recalls, or TSBs
As of early 2026, there are no specific recalls or widespread Technical Service Bulletins (TSBs) from Ford for intake manifold gasket failures on the 2014-2019 Ford Taurus. This is generally considered a standard wear-and-tear repair item that becomes more common as the vehicle ages. Searches on the National Highway Traffic Safety Administration (NHTSA) database show no actions related to this specific part and vehicle combination.
| Part Type | Part Cost | Shop Labor Cost | Estimated Total Cost |
|---|---|---|---|
| New Aftermarket (Budget) | $10 - $30 | $170 - $250 | $180 - $280 |
| New Aftermarket (Premium) | $50 - $70 | $170 - $250 | $220 - $320 |
| New OEM | $40 - $70 | $170 - $250 | $210 - $320 |
Cost estimates are approximate and can vary based on your location and the specific repair shop. The provided aftermarket part price is at the low end of the budget range.
Frequently Asked Questions (FAQ)
Can I replace the plenum gasket myself?
This job is manageable for an experienced DIY mechanic. It requires removing the air intake system, throttle body, and fuel rail to access the upper and lower manifolds. You will need a good socket set, a torque wrench for proper reassembly, and about 3-5 hours. For beginners, it might be best left to a professional due to the number of components involved.
Should I use sealant on the new gaskets?
Generally, no. Modern molded rubber gaskets like those used on the Taurus are designed to be installed dry. The gasket's shape provides the necessary sealing force. Applying RTV sealant can interfere with the seal and potentially cause leaks. Always follow the instructions provided with your specific gasket set.
What is the difference between an upper and lower intake gasket?
The 3.5L V6 engine uses a two-piece intake manifold. The lower gaskets seal the base of the manifold to the cylinder heads (six individual gaskets are required). The upper gasket, often called the plenum gasket, seals the two halves of the intake manifold together. Since the upper half must be removed to access the lower gaskets, you should always replace them as a set.
What happens if I don't fix a leaking intake gasket?
Driving with a minor vacuum leak will lead to poor engine performance, rough idling, and decreased fuel economy. If the leak is severe, it can cause stalling and misfires. If your vehicle's gaskets also seal coolant and there is a coolant leak, ignoring it can lead to engine overheating and catastrophic engine damage.
Technical Specifications
OEM Part Numbers: AT4Z-9H486-A (Upper Plenum Gasket) AA5Z-9439-BA (Lower Intake Gasket, 6 required)
The 3.5L V6 engine requires one upper plenum gasket and six individual lower intake manifold gaskets. Gaskets are typically made from molded rubber designed for a dry-fit installation.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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