We take gasoline for granted.

Bad Throttle Position Sensor. The throttle position sensor monitors the throttle valve’s. This is because a rich fuel mixture is over-saturated with gas, causing ignition problems. Mixtures that have too much air and not enough fuel are lean and tend to reduce the amount of power available under load and can cause stalling. In both cases, a professional carburetor inspection and adjustment are necessary to correct the problem.

For most of us, it’s as simple as putting gas in, and thendriving away. These days, it’s very rare that you’ll get bad gas from a gasstation. In over 18 years as an auto mechanic, I’ve never seen someone’s enginedamaged by bad gas.

Bad gas doesn’t combust evenly – which can cause your engine to sputter or ping. Listen to your car both at idle and while driving at moderate speeds. These noises aren’t the smoking gun on their own, because they can also be caused by a bad fuel filter. 3: Stalling While Driving. Empty fuel tank. If your low fuel warning light is on, and it has been on for a while, this is. Unclog or replace gas cap if air vent is blocked. Change air filter if it’s clogged or dirty. Prime engine if equipped with small rubber bulb. Replace fouled or dirty spark plug.

It just doesn’t happen as much as it used to.

But it does still happen.

Back in 2012, over 4.7 million gallons of gas were recalled from BP stations in Chicago, Northwest Indiana, and Milwaukee. The bad gas, in this case, was contaminated with polymer residue, which doesn’t burn in automotive engines and can cause damage to the engine.

Generally speaking, bad gas is usually the result of contaminationfrom your fuel tank or fuel line. It can be the result of your car sitting foran extended period of time, or from water making its way into the fuel tank.

By the time you’re finished reading this guide, you’ll be anexpert in diagnosing if your car actually has bad gas, as well as correctingthe problem if it becomes an issue.

You’ll learn everything you need to know – and probably somethings you don’t need to know.

What Causes Gas To Go Bad?

Gasoline doesn’t stay good forever. The countdown starts assoon as you expose gasoline to air. After around 30 days or so of sitting inyour fuel system, your gasoline starts to oxidize.

When gasoline oxidizes it can gunk up your fuel system by turninginto varnish which can coat your fuel system and engine. As gasoline degrades,it goes from clear in color to looking more like apple cider. This “apple cider”gasoline then begins to gum up your fuel system and your engine.

Even worse, today’s gasoline often contains ethanol. When thesedeposits form, the ethanol in them attracts water from the atmosphere (it’s hydrophilicfor all you chemistry nerds).

Generally speaking, old gas in your car isn’t the end of theworld if you’ve let it sit for only a couple of months, but if your car hasbeen sitting for 6 months or more, you can run into some problems and you mayneed to use something like Seafoam.

We’ll get into what exactly you need to do in a bit.

Age is the most common cause of bad gas, but it’s far fromthe only one.

Water can also get into your gas tank. This can be caused by a loose gas cap, or from condensation. It’s also possible that water can make it in from the pump itself – although this is getting more and more uncommon.

Besides age and water, you may also have contaminated gasfrom a cracked fuel line, or from flakes coming from your gas tank.

What Are The Symptoms Of Bad Gas In Your Car?

Bad gas is fuel that doesn’t combust as expected. With thatin mind, most of the symptoms are related to the car not running as expected.

Your car relies upon fuel being delivered to the combustionchamber and igniting optimally. When this doesn’t happen, the car oftenhesitates and suffers from a lack of performance. With that in mind, somesymptoms of bad gas to look out for include:

1: Difficulty Starting Your Car

If your car cranks but won’t start, it could mean that youhave bad gas. Contaminated gas doesn’t provide enough power to start theengine. However – if your engine doesn’t start, you shouldn’t automaticallyassume you have bad gas. Anything from bad spark plugs to a busted fuel pumpcan cause your engine not to start.

If you have a lot of bad gas in your tank, this can causeyour car not to start in some cases.

2: Sputtering Or Pinging Sounds When The Car IsIdling/Driving

Bad gas doesn’t combust evenly – which can cause your engineto sputter or ping. Listen to your car both at idle and while driving atmoderate speeds. These noises aren’t the smoking gun on their own, because theycan also be caused by a bad fuel filter.

3: Stalling While Driving

If your gas is contaminated with sediment or with water, it’spossible that your car may stall while you’re driving because the fuel is notcombusting correctly. This only happens in extreme cases, so more likely thannot, it’s not something you’ll have to worry about.

4: The “Check Engine” Light Coming On While Driving

Bad fuel can cause your car to run lean. If you have an OBD-II code reader, the code will almost always relate to your engine running lean.

5: Burning More Gas Than Usual

When you have bad gas, your engine will have to work harderthan normal to produce the same amount of power. This can show up as your car burningmore fuel than usual. On its own, this isn’t a smoking gun, but if you noticeit together with the other symptoms, pay attention.

6: Trouble Accelerating

If you have bad gas, it’s common for you to have troubleaccelerating or going up hills or other steep inclines because bad gas doesn’tburn correctly.

7: Speed Changes While Driving Without Pressing The Gas Pedal

Bad gas can also cause your car to abruptly change speedswhile driving. You may notice a sudden slow down, followed by a surge of speed.

What Are The Symptoms of Water In Your Gas Tank?

The symptoms of water in your gas tank depend on how much water gets into your gas tank. If there’s only a little bit of water, you might not notice it at all.

But if there’s a lot of water in the tank – you’ll definitelyknow.

The main thing to watch out for is hesitation when you tryto accelerate. When there’s water in your gas, your engine won’t be able toperform up to standard. The more water in your gas, the worse this will get.

The other symptoms I’ve already covered above.

So, Can Bad Gas Damage Your Car?

The answer is yes – but for it to get to that point you need to really let things go for a long time. Bad gas can form deposits that can cause issues in your engine. Again, this is very rare and probably won’t happen, but it’s good to know.

However, if you get bad gas from a gas station, you could be in for quite the repair bill. Although I’ve never seen the damage personally, I have seen reports ranging from $1,000 to $2,500+.

Can A Bad Gas Cap Cause Your Car To Stall

How To Get Reimbursed For Bad Gas

As I previously mentioned, most bad gas is probably not thekind you’ll be able to be reimbursed for. For example, if your gas goes badbecause it’s old you’re not going to get reimbursement.

However, if you put gas in your car and it almost immediatelystarts coughing and sputtering, then you may be on to something.

To prevent yourself from getting the shaft, you need to makesure you get a receipt. If you can prove you got bad gas from a gas station,then you’ll be able to get reimbursement.

More likely than not, you’ll be paid through the gas station’sinsurance policy. You may also want to call your state’s consumer protectionagency to report that you got bad gas to prevent others from getting burned asyou did.

With that being said – how can you be sure if you have badgasoline or not? You test for it.

How to Test For Bad Gasoline

Does A Bad Gas Cap Cause Stallings

The first thing you should do is ask yourself if it’s possible that your gasoline was contaminated due to your own error. Whether that was through letting your car sit, or through a loose gas cap, or something similar.

If you can rule these out, then it’s somewhat difficult to testthe gasoline without special tools.

A fuel test procedure and kit (without sending out to a lab)involves 3 steps.

1. The first involves lowering a probe to the bottom of the tank with a paste that changes color if it touches moisture. The probe almost resembles a bicycle cable in a clear sheathe. This requires the probe and the color-changing paste.
2. The second involves retrieving a sample of the gasoline. Place the gasoline in a graduated cylinder. Add some amount of windshield washer fluid. Cork the sample and shake the tube. Wait until it settles. Compare how much gasoline you put into how much is left after everything settles. This shows how much alcohol is in the fuel. It should be no more than 10%. All this test needs is a graduated cylinder that can survive gasoline. This is the easiest thing to acquire.
3. The third involves retrieving a sample of the gasoline. This test measures the volatility of the gas known as Ried Vapor Pressure and requires another special testing tool. Chill the gasoline and tool on ice for 30 min. Pour the fuel into the tool and close it. Place the tool into hot water for 10 min and measure the water temperature. Read the pressure from the gauge on the tool. Compare the pressure and temperature to a table that comes with the tool.

Can A Bad Gas Cap Cause Stalling

How To Get Water Out Of Gas

If you have water in your gas, the first step is to figureout how much water you have in your tank. If your car is still drivable,chances are you don’t have too much water in your gas tank.

However, if you’re having serious performance issues – then you’llneed to go another route.

In this case, you have a few options.

They include using a product like Heet or by doing it yourself with dry isopropanol alcohol.

Considering Heet is about $3 on Amazon, it’s usually theeasiest option.

If Heet or isopropanol alcohol doesn’t fix the problem – thenyou’ll need to siphon the gas out of your tank.

Get a fuel siphon, and then feed the tube into your gas tank and get pumping. Pump the siphoned fuel into a clear container so you can inspect it, and then refill your gas tank with good dry fuel.

How To Fix Bad Gas

Fixing bad gas, on the other hand, is much simpler. If you have true bad gas – not old gas, or waterlogged gas, then you’ll need to siphon the gas out of your tank and pump new gas in.

Don’t mess around with this, because bad gas can causedamage when it does happen, even if it only happens rarely.

One of the most common issues your Nissan Altima is likely to develop is a stalling problem. The most challenging part of diagnosing a stalling problem is reproducing the conditions that led to the stall in the first place. Stalls can happen at any time, and it can be incredibly jarring when it does happen.

Before troubleshooting any automotive issue, including stalling issues with the Altima, make sure that you check the vehicles trouble codes with an OBD2 scanner. Trouble codes are always a great place to start diagnosing problems on today’s modern computer controlled vehicles. Without them, you are in the dark.

These codes are vital to diagnosis. They are often specific enough to get you all the way to the problem, or pretty darn near. If you don’t own/want to buy a scanner, most local parts stores will run a scan for you at no cost (they want to sell you the parts).

Nissan Altima Stalling Problem Causes

Here are some of the issues that cause the Altima to stall out. Remember, a vehicle needs air, fuel, and spark to run. It needs them in the right quantities and intervals, or it won’t run right.

Fuel

Fuel issues are one of the most common reasons that a vehicle would stall out, that includes your Nissan Altima.

• Bad gas- can cause an engine to stall out. Water in the gas tank can also cause gas to not fire properly. If there were no other symptoms and suddenly you find that the vehicle is running very rough, bad gas could certainly be the problem. Here’s a good article on all the symptoms of bad gas.
• Air Fuel Mixture– If the air/fuel mixture is off, your Altima can stall out. Usually it’ll be a bad sensor reading, vacuum leak, or other problem that’ll cause the air/fuel mixture to be wrong.
• Bad Fuel Injectors– If the fuel injection system is allowing too much or too little fuel into the combustion chamber, than your Altima will stall out. Or, it just may not be able to properly atomize the fuel anymore. Here’s more on Nissan Altima bad fuel injector diagnosis.
• Not Enough Fuel– The fuel pump may not be able to provide the fuel pressure needed for the engine to run properly. When it asks for a lot of fuel, instead of taking off, it stalls out with the demand. This can be caused by the fuel pump or fuel filter.

Engine Timing

If your Nissan Altima’s engine timing is off, it’s going to stall out, misfire, and altogether not run properly. Here are some of the more common causes of an engine timing problem:

• VVT Problem– Many modern engines are equipped with Variable Valve Timing. This allows for the engine to be in the “sweet spot” of power or economy depending on how hard you are pushing the gas pedal. If there is a VVT issue, it’ll often throw trouble P0010, P0011, or other related trouble codes. This is often the cause of the stalling.
• Timing Chain Jumped– If your timing has jumped a tooth or two, it’ll definitely stall out. Just know, that if it jumped a tooth, it’s only a matter of time before it jumps more or breaks all of the way. If that happens you are going to go from misfire to un-drivable. Here’s more on timing chain jumped symptoms.

Sensor Issues

Your Nissan Altima uses a series of complex sensors to report what is going on to the ECU. The ECU then uses this information to adjust the timing, air fuel mixture, and more. When one of them goes wrong, it can lead to stalling for sure.

• Throttle Position Sensor– The throttle position sensor is typically located on the gas pedal. This sensor is responsible for telling the engine how much air and fuel to allow in. It is very rare these days to be actually directly controlling the amount of fuel and air entering the engine directly. These days the computer handles all of that. This serves two purposes. The first is that by limiting the amount of torque when you push the gas pedal for a second or two, engine life is increased by reducing the stress on it during takeoff. The second is improved fuel economy. Here’s a great article on diagnosing a bad throttle position sensor from cars direct.
• MAF/MAP Sensors– These sensors are responsible for air measurement. When they go bad, your Altima may not be letting in the right amount of air for a quality air/fuel mixture. Here’s more on diagnosing a bad mass airflow sensor.
• Oxygen Sensor– The oxygen sensors measure the exhaust gasses after they exit the combustion chamber. The ECU uses this data to make adjustments to the air/fuel mixture. If one of them has gone bad, then it could lead to stalling.

There are many other sensors that can cause your Altima to stall. These were just some of the most common ones.

Dirty Throttle Body

A dirty throttle body can lead to stalling in your Altima. If you let off of the gas coming to a stoplight and it stalls for a second or two and recovers itself, it very well could be a dirty throttle body that is causing the problem. Here’s a great YouTube video from EricTheCarGuy. on how to clean a throttle body.

A dirty throttle body may not trigger the check engine light. So, if your stalling happens when coming to a stop, and the check engine light is on, it may be worth taking a look at it.

Torque Converter

All modern torque converters “lock”. What this locking does is provide a true mechanical connection from the engine to the wheels. This eliminates some driveline power loss and improves fuel mileage. If the converter doesn’t unlock, then the engine will stall much like a manual vehicle does when it doesn’t have enough speed to carry a gear. It’ll often throw code P0740.

Oil Consumption

If there is almost no oil left at all, the engine could be on its way to locking up. It’s worth a look, especially if you can’t remember the last time that you checked.

Conclusion: Nissan Altima Stalling Diagnosis

As you can see above, there are many different reasons that your Altima could be stalling. Please, please have your trouble codes read if there is a check engine light on at all. It can really help narrow down what you need to do. If there is anything that you would like to add, please drop a comment. Good luck!