Rough idle refers to uncomfortable driving and low RPMs below 600. Your car will shake in highly harsh idling conditions; therefore, you cannot drive the car smoothly. Do you know why rough idle occurs?
Multiple reasons are there. Different parts of the car may cause the car to rough idle while driving. If any part of the car goes wrong, you will get rough idling, not showing you the exact reason.
Can a gas cap cause rough idle?
A Gas cap can cause rough idle because of insufficient fuel pressure. If the gas cap goes bad, it will stop providing the right fuel pressure to the engine. Therefore, the engine will fail to produce enough power to run the car smoothly; then, the rough idle will occur.
Some reasons are there which cause the gas cap to cause rough idle. Among them, the loose fuel cap is one. It will directly hamper the engine and stop the flow of fuel pressure. Consequently, the machine will be idle, and the power will go below 600 RPMs.
We found two such reasons why the gas cap causes rough idle. They are:
Loose gas cap:
When the gas cap is loose, it will fail to provide the required fuel pressure. It will also cause the check engine light to come on; eventually, the engine will decrease its power, and you will experience rough idle.
It will not stop unless you check the gas cap and tighten it. You have to be prompt and check why the check engine light comes on and what causes the rough idle. It will be better to check the gas cap regularly and tighten it if needed.
Bad or failing gas cap:
A bad gas cap will also cause a rough idle. It will damage the fuel tank and get loosened eventually.
Also, the bad gas cap will hamper the fuel pressure, affecting the engine power. When you check the gasoline, you must check the gas cap.
Also, a failing gas cap will hamper the entire fueling system and cause rough idle. Check the gasoline and gas cap if you ever experience rough idle or unsmooth driving.
How does a gas cap cause rough idle?
When it goes wrong or fails, a gas cap will cause rough idle. Mainly, if you use the gasoline over the years, and it remains unchecked, you will suddenly get rough idling whether your gas cap is bad or fail to provide the required fuel pressure.
It will directly affect the engine and stop producing the above 600 RPMs. It’s a standard to drive smoothly. A failing gas cap will also fail to provide the right amount of fuel to the engine, which will lead to the rough idle indirectly.
So, you should check the gas cap and take steps to repair it. Sometimes you might get a loose gas cap. In that case, you need to tighten it and make sure the fuel pressure is high enough.
What problems can a loose or failing gas cap cause?
A loose or failing gas cap causes several problems to the engine, which will assist the car to rough idle.
Fuel Pressure:
Fuel pressure is directly associated with the gasoline and gas cap. If the gas cap goes bad or fails, it will hamper the fuel pressure.
The engine will not get enough fuel to run smoothly; therefore, it will cause rough idle and shaking.
Damaging Engine:
Fuel pressure will also increase the engine temperature, which will damage the engine.
If your engine can’t get enough fuel to run smoothly, it will overuse the strength and be rough. As a result, it will produce heat and damage itself.
Check Engine Light:
The bad or loosen gas cap will cause the check engine light to come on. It will be a serious concern for the driver. You cannot drive the car until you solve the issues and the check engine light goes off.
Get dust and bacteria:
When the gas cap is terrible or loosened, outside dust and bacteria will enter the gasoline tank. It will ruin the fuel quality.
When you drive the car, your engine will take that contaminated fuel. If you use the dust and bacteria mixed fuel for a long time, the engine will damage.
Increase Cabin Temperature:
When your gas cap goes bad, it will indirectly increase the cabin temperature since the engine will get hot and disclose the temperature.
It’s another concern for the driver to drive with a bad gas cap. You should repair the gas cap & avoid rough idle.
Rough Idle:
Last but not least, the loose or failing gas cap will cause the rough idle. All the problems will reduce the engine’s power and turn into a rough idle. You shouldn’t drive until you solve the problem.
How tight should you tighten the gas cap?
You should tighten it until the gas cap ticks three times. There is no standard number to ensure the gas cap tightening, but you should check at least two consecutive times. It will help you reduce the risk of getting a loose gas cap.
A three-time tick is a random number. It might be two or four, depending on your effort. If you carefully tighten the cap, one-tick would do.
When you randomly close it, it will take several ticks to ensure the gas cap fittings. So, be careful to close the fuel cap.
How often does a gas cap go bad?
A gas cap doesn’t go wrong frequently. However, five months will be an excellent time to use the same gas cap. Your gas cap might go wrong after every three to five months.
You should check it pretty much every month and open the gasoline. Look at the car and find out if it is bad or damaged. You should not make any mistake or delay replacing the gas cap as soon as you find the bad one.
How to tell if your gas cap needs replacing?
When you check the gasoline and gas cap, you should spend some time and notice them carefully. Try to find out the damaged part, and it will be better to check the gasoline and gas cap together. It will help you to notice the damage.
You can also tell by checking the engine power. If it goes below 600 RPMs, your gas cap might be wrong or loose.
Also, you can look at the engine light. When the check engine light comes on, your gas cap might fail to provide the exact fuel pressure due to its damaging part.
Can you drive with a loose gas cap?
You can drive with a loose gas cap. Although it is not a good practice to drive with a bad gas cap, you can do it for time. If you have any urgency and don’t have any other option, you can go for a couple of miles.
In the meantime, you must look at the engine power of the RPMs. If it goes below 600, your car will start shaking. Also, if you drive with a loose gas cap, you will experience rough idle. You will not get any smooth driving.
It will not be wise to drive with a loose gas cap. Your engine might stop working, and the check engine light will come on. Altogether, it’s not a good practice to drive with a loose gas cap.
Final thoughts
If a gas cap goes wrong or loose, it will cause rough idle. It hinders the fuel pressure and affects the engine power directly. Therefore, the engine fails to produce enough power. It ultimately causes a rough idle and an unsmooth driving experience will bother you.
I am an automotive enthusiast and have been interested in cars since I was a little kid. I have worked in the automotive industry for many years and have extensive knowledge of vehicles and their engines. I am a father of two and I love spending time with my family.
Read more about the author here.
