1999 GMC Jimmy Smells Like Gas

Identifying Potential Causes of Gas Smells in Your 1999 GMC Jimmy and Safety Precautions to Take

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Reviewed by
Bo Fader
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 GMC Jimmy 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 GMC Jimmy 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.

For most vehicles, the only symptom will be a check engine light or fuel tank filler cap light illuminating on the driver instrument cluster. This is to signal that there is an evaporative emissions (EVAP) leak. In some situations, the vehicle may take longer than normal to start, or, more rarely, the engine may not start at all. on-board diagnostic (OBD) trouble codes will refer to EVAP system failures such as a small or massive EVAP system leak. Lastly, the powertrain control module may notice a lean running condition, which could even lead to random and infrequent misfires.

What are the potential causes and diagnostic steps for a gas smell in a 1999 GMC Jimmy?

When dealing with a gas smell in your 1999 GMC Jimmy, it's essential to adopt a systematic diagnostic approach to identify the underlying issue effectively. Start with a visual inspection of the vehicle, focusing on areas where fuel leaks are likely to occur, such as the fuel lines, injectors, and tank. A common culprit is a faulty fuel cap, so ensure it is securely fastened and in good condition to prevent vapor escape. Next, examine the evaporative emissions system, including the charcoal canister and purge valve, for any signs of damage or leaks. Don't overlook the exhaust system; a cracked manifold or damaged gasket can also contribute to a gas odor. If these initial checks do not reveal the source, using a diagnostic scanner to check for error codes related to the fuel system or emissions can provide further insights. If the problem persists, consulting a mechanic for a comprehensive inspection is advisable to ensure your vehicle is safe and functioning correctly. By following this structured approach, you can efficiently diagnose and address the gas smell issue in your GMC Jimmy.

What are the common causes of a gas smell in a 1999 GMC Jimmy?

When you detect a gas smell in your 1999 GMC Jimmy, it’s crucial to investigate the source promptly, as it can indicate serious safety concerns. One common culprit is a leaking fuel injector, which can emit gas vapors into the cabin. Additionally, inspect the fuel lines for any cracks or damage, as these can also lead to fuel leaks and a strong gasoline odor. Don’t overlook the gas cap; if it’s loose, damaged, or missing, it can allow fuel vapors to escape. Another potential issue is a leak in the Evaporative Emissions Control System (EVAP), which may involve a faulty purge valve or other components. Lastly, check for any leaks in the fuel tank itself, as this can be a significant source of gas smell. Addressing these issues not only enhances your vehicle's performance but also ensures your safety on the road. If you’re unsure about diagnosing or fixing these problems, consulting a professional mechanic is always a wise choice.

How urgent is it to address a gas smell in a 1999 GMC Jimmy?

Addressing a gas smell in your 1999 GMC Jimmy is not just a matter of convenience; it is a critical safety issue that requires immediate attention. Gas leaks can lead to catastrophic consequences, including the risk of fire, which endangers both the vehicle's occupants and others on the road. Moreover, inhaling gasoline fumes poses serious health risks, with symptoms ranging from dizziness and headaches to more severe respiratory issues with prolonged exposure. Ignoring this warning sign can also lead to further damage to your vehicle, resulting in costly repairs down the line. Therefore, if you detect a gas smell, it is essential to act quickly. Start by inspecting the fuel lines, connections, and the fuel tank for any visible leaks. If you are not comfortable performing these checks yourself, it is advisable to consult a professional mechanic. Taking prompt action not only ensures your safety but also helps maintain the integrity of your vehicle.

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