1999 Mercury Mystique Smells Like Gas

Addressing Gas Smells in Your 1999 Mercury Mystique and Safety Measures

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Reviewed by
Andrew Hajjar
Written by RepairPal Car Genius
Updated January 14, 2025
0%
15% chance it's the
Gas Cap
0%
40% chance it's the
Emissions Control System
0%
45% chance it's
Something else
The most common reasons a 1999 Mercury Mystique smells like gas are the gas cap, the fuel system, or the emissions control system.
  • Gas Cap: A loose or damaged gas cap can cause fuel vapors to escape, triggering the check engine light and potentially affecting fuel system pressure.
  • Emissions Control System: A faulty emissions control system can lead to increased hydrocarbon emissions and trigger the check engine light due to malfunctioning components like the EGR valve or O2 sensors.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 1999 Mercury Mystique smells like gas?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

A failing catalytic converter can cause a vehicle to fail emissions tests and turn on the check engine light. The exhaust might have an unusual smell. A restricted catalytic converter can result in a loss of engine power.

» LEARN MORE: How to tell if your catalytic converter is failing

The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. The canister may also cause difficulty starting the engine, a rough idle, and poor fuel mileage.

When the fuel filter begins to clog, the engine suffers from fuel starvation. This will cause a significant reduction in power and may also cause a misfire. These conditions may be intermittent, or constant and worsen over time. As the issue progresses, the engine may being to stall immediately after starting, fail to start, hesitate under throttle, or stall at particular angles on hills.

The check engine light will illuminate any time there is a failed EVAP system test. This will be indicated by the various on-board diagnostics trouble codes that are stored in the vehicle's memory. Also, in some models, there may be a popping sound accompanying the check engine light, as the leak detection pump continuously attempts to pressurize the fuel tank. A fuel tank leak may also cause difficulty starting the engine, a rough idle, and poor fuel mileage. When a fuel tank is simply corroded to the point of failure, the exterior tank condition rarely shows damage. The inside of the fuel tank will be rusted or corroded, and rust flakes or other debris may be floating in the fuel.

What are the potential causes for a gas smell in a 1999 Mercury Mystique, and how should I diagnose the issue?

When faced with a gas smell in your 1999 Mercury Mystique, it's essential to adopt a systematic diagnostic approach to pinpoint the source of the problem. Start by inspecting the fuel system for any visible leaks, focusing on the fuel lines, injectors, and tank, as these are common culprits. If no leaks are apparent, examine the fuel injectors closely for signs of malfunction, as a faulty injector can lead to fuel leakage and odors. Next, assess the evaporative emissions system, which plays a crucial role in containing fuel vapors; check components like the charcoal canister and purge valve for any signs of wear or damage. Don’t overlook the gas cap, as a loose or damaged cap can easily allow vapors to escape, contributing to the smell. Finally, inspect the exhaust system for leaks, as exhaust fumes can sometimes mimic the scent of gasoline inside the cabin. By following this structured approach, you can effectively diagnose the issue and take the necessary steps to resolve it, ensuring your vehicle remains safe and odor-free.

What are the common causes of a gas smell in a 1999 Mercury Mystique?

When addressing a gas smell in a 1999 Mercury Mystique, it's essential to identify the common causes that may be contributing to this issue. A leaking fuel injector is often a primary suspect, as it can release gas vapors into the air, leading to a noticeable odor. Additionally, inspect the fuel lines for any cracks or damage, as these can result in significant gas leaks and intensify the smell. The gas cap is another critical component; if it is loose, damaged, or missing, it can allow fuel vapors to escape, creating a gas smell both inside and outside the vehicle. Problems with the evaporative emissions control system, including a malfunctioning charcoal canister or purge valve, can also lead to gas odors. Lastly, a leak in the fuel tank itself poses a serious risk and should be addressed immediately. While some preliminary inspections can be conducted at home, it is crucial to consult a qualified mechanic for a comprehensive diagnosis and resolution to ensure safety and prevent potential hazards.

How urgent is it to address a gas smell in a 1999 Mercury Mystique?

Addressing a gas smell in your 1999 Mercury Mystique is not just a matter of convenience; it is a pressing safety concern that should be treated with the utmost urgency. Gas leaks can lead to catastrophic outcomes, including the risk of fire, which endangers both you and your passengers. Moreover, the inhalation of gas fumes poses serious health risks, potentially causing symptoms such as dizziness, headaches, and nausea that can impair your ability to drive safely. Beyond safety and health implications, neglecting a gas smell can also lead to decreased vehicle performance, resulting in poor fuel efficiency and possible engine damage over time. Therefore, if you detect a gas smell, it is essential to investigate the source immediately and take appropriate action to mitigate these risks, ensuring both your safety and the longevity of your vehicle.

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