I am getting horrible gas mileage.

I am getting horrible gas mileage.

I drive an 07 corolla that is supposed to get 34 mpg but I am only getting about 22 mpg on the highway. I have checked tire pressure, replaced both 02 sensors, replaced both air filter and cabin air filter, replaced mass air flow sensor, replaced fuel injectors, put seafoam cleaner in gas tank, and bought new tires. I can't figure out why I am getting such bad mpg! I have spoken with several mechanics and no one can tell me. I even called Toyota and they said check tire pressure. Any ideas?

My car has 150000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :

There are a number of things that can cause poor fuel mileage. A faulty camshaft position sensor is one of them. The camshaft position sensor is a magnetic sensor that monitors camshaft speed to regulate ignition timing and fuel injection timing. It gathers and sends information about the car’s camshaft speed (and as a result the position of each piston) to the car’s electronic control module. This information is received by the computer, which then uses this data to further calculate the time of ignition and the timing of fuel injection required by the engine. When this is not working properly, you may experience a drop in power, poor idling, poor fuel mileage and problems starting the vehicle.

A clogged or dirty EGR valve may also cause poor fuel mileage. The EGR valve is a small component designed to allow the flow of exhaust gases into the intake manifold in controlled amounts. Whenever you start the engine, the valve comes alive and waits in a closed position, blocking the flow of exhaust gases. Once the engine reaches operating temperature and speed increases, the valve, either through vacuum or electronic control will gradually open, allowing burned exhaust gases to enter and combine with the air-fuel mixture inside the combustion chamber. When the EGR valve is clogged or dirty, as they are prone to, it may not function properly causing the engine idle rough, stall at idle speeds, cause the car to get poor fuel mileage, or emit a strong smell of fuel due to excess hydrocarbons which also results in failing emissions tests.

A clogged or failing catalytic converter can cause the vehicle to have poor fuel economy. As you may already know, the catalytic converter converts toxic exhaust gases into less harmful pollutants that are suitable to be expelled into the atmosphere. When this is clogged, this causes these gases to be backed up into the exhaust system not allowing the engine to breathe properly. When this happens, the engine is forced to work much harder to expel these gases. This often results in the engine bogging down, hesitating, shaking and causing very poor fuel economy. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

lack of maintenance (dirty filters, worn spark plugs, clogged catalytic converter etc.) If you want to find out the reason for your poor fuel mileage, take your Corolla to your trusted mechanic and have the issue diagnosed by a professional. Good luck.

Misaligned Tires: Tires that are low or out of alignment can lead to a drop in fuel efficiency. Checking the tire pressure and have the alignment checked on regular basis can help prevent this problem. Defective Fuel Pump: Fuel delivery issues can drastically affect fuel efficiency.

A dirty air filter restricts airflow and makes it harder for your engine to breathe. This places additional strain on your engine and reduces its efficiency. As a result, you`ll notice a decline in fuel economy. To avoid this, regularly clean or replace your air filter according to the manufacturer`s recommendations.

Try to avoid idling in traffic

If you think you`re going to be there for a while, turn your engine off if it is safe to do so. If you`re not moving but the engine is still running, your fuel efficiency hits an all-time low.

The best thing you can do to keep your car`s gas mileage up is to perform regular oil changes with the type of oil specified in your owner`s manual. High mileage engine oils may help reduce oil leaking and oil consumption but it will take away some of the potential fuel efficiency.

Aside from mechanical issues, other factors can affect gas mileage. Miskelley says bad alignment, improperly inflated tires, poor tread and driving habits can make a difference in how far a gallon of gas goes. “Poorly maintained tires can cause your car to pull harder and do extra work to get going,” says Miskelley.

When an engine misfires, it leads to poor engine performance, which in turn also affects the car`s fuel economy. Thus, bad spark plugs can decrease engine efficiency and force it to consume more fuel, thus increasing the car`s fuel consumption.

Sensors include coolant temperature, intake air temperature, mass-air flow, throttle position, oxygen (O2), crank trigger, cam triggers, exhaust gas recirculation (EGR), manifold air pressure, evaporative emissions canister purge, and automatic transmission.

Press and hold the trip reset button near the odometer until “Trip A” appears on the central screen. Turn the key back to “Off.” While pressing the button to reset the trip, turn the key back to the “On” position. Keep holding the trip reset button until the miles section of the odometer flashes zero.

One of the keys to saving fuel is driving at a constant speed, cruise control can do this effectively on flat surfaces, making your driving as fuel efficient as possible by negating unnecessary acceleration.

Using a vehicle`s air-conditioning system increases its fuel consumption more than any other auxiliary feature. An air-conditioning (a/c) system can increase fuel consumption by up to 20% because of the extra load on the engine.

A car consumes more fuel in lower gears when accelerating. If the engine`s not pulling, shift down instead of pressing the throttle. Shifting up at 2,000 rpm (1,500 rpm for diesel) gives the best mix of speed and economy.

This makes the Corolla more powerful than the Honda Civic or Mazda 3 or Hyundai Elantra. On the other hand, it still averages less than 7 litres per 100 kilometres with a fuel economy rating as low as 5.8 litres per 100km on the highway.

The Corolla mileage is 11.3 to 13.4 kmpl. The Manual Petrol variant has a mileage of 13.4 kmpl. The Automatic Petrol variant has a mileage of 13.4 kmpl.

Generally speaking, yes. Cruise control can help you become more fuel-efficient and can help you save an average of 7-14% on gas thanks to its ability to maintain a continuous speed. In comparison, the constant change in acceleration and deceleration of the driver placing their foot over the pedals can eat more gas.

1. Increased fuel efficiency. Replacing a clogged air filter can increase fuel efficiency and improve acceleration, depending on your car make and model. When you realise that, it makes sense to regularly replace your air filters.

One of the first signs of a failing fuel rail pressure sensor is poor fuel economy. If your car suddenly seems like it`s using more gas than usual, it could be due to a problem with the sensor. Additionally, if your car starts to hesitate or stall when accelerating, this could also be a sign of a failing sensor.

Fuel Efficiency

If you drive a newer model, you can expect a clean cabin air filter to increase acceleration by 6-11%. Bottom line, a clean air filter will improve clean air flow to your vehicle`s engine, improving gas mileage.

Anything that is listed as less than 6-litres/100km or more than 16.5km/1-litre is considered to be pretty good. The first (and most common) reference is litres per 100km (litres/100km).

The Energy Saving Trust says that the most efficient speed you can travel in a car in terms of achieving the best fuel economy is 55-65mph. Any faster, though, and the fuel efficiency decreases rapidly.

STA-BIL 360 Marine Ethanol Treatment and Fuel Stabilizer

It provides ultimate treatment and protection against ethanol-blended fuels. It`s a proven product that stabilizes fuel for up to one year. The product will not only help to improve power in your vehicle, but also improve your fuel efficiency.

Even though many people believe that putting a brand new engine resets mileage, it is just a misconception. The odometer counts the mileage of the car as a whole and not for the specific parts.

Compression

Increasing compression is the most productive way to increase horsepower. Build compression into your engine and you build in power. In more than a century of internal combustion, there has never been a more common sense way to make power. But be careful about how you raise compression.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

My gas cap will not open. I can get a new cap but how do I get the current one off?

ANSWER : Hi there. Unfortunately, there is no black & white step for removing a broken gas cap. If the gas cap is stripped or spinning around, it has to be carefully drilled out. This should be completed by a professional mechanic to avoid mistakes and debris falling into the fuel cell. If you live in one of our service areas, one of our professional mobile mechanics can come to your location and complete the gas cap replacement.

Read Full Q/A … : I am getting horrible gas mileage.

Car is squealing but not when a/c is off, no power when pressing on gas, hesitates to get fuel & has horrible gas mileage& more

ANSWER : Hi there. I think your best bet is to have one of our professional mechanics come to your location and complete a car is getting poor gas mileage inspection. This will allow them to inspect your fuel system and ignition system to determine what components might be contributing to your issue. The squealing noise is either a drive / serpentine belt, or AC belt, as the older 90’s Nissan’s had a separate belt for the AC pump.

Read Full Q/A … : I am getting horrible gas mileage.

Low gas mileage

ANSWER : Hello. The fuel mileage rating on most vehicles is a rating estimate of the fuel mileage you should get. The problem with this rating you see in the windshield is based on city or highway driving. Both of these ratings are done in a controlled manner with no A/C or accessories used during the test. Your actual mileage will vary depending on the traffic congestion, traffic lights per mile, and other things like tires and tire pressures. Even the altitude you are at will get better mileage in higher altitudes and less if you live near sea levels. If you would like to have this looked at further, a qualified expert from YourMechanic can come to the site of your car to diagnose the fuel economy concern.

Read Full Q/A … : I am getting horrible gas mileage.

Bad gas mileage on the highway

ANSWER : There are many things that can cause the fuel mileage to go down or be lower than what others are getting. The most important thing is to not use performance parts like filters or sensors. These only increase the power and use more gas. Also, put the tires to their most optimal pressure settings. Make sure all tune-up parts are new like the plugs, filters, wires, and belts. Then practice good driving habits like coasting longer before stoping, accelerating slower, and braking slower. Not speeding will also save fuel. Do not use A/C unless it is needed. All these things will help. Finally, you can have the computer scanned for any pre-existing problems that may affect fuel mileage.

Read Full Q/A … : I am getting horrible gas mileage.

Bad gas mileage

ANSWER : Hello there. A decrease in fuel milage can be attributed to a few different faults. The most common causes are leaking fuel injectors, oxygen sensors, coolant temperature sensors, vacuum leaks or exhaust leaks. A qualified technician, such as one from YourMechanic, will check all of these for proper operation and can make any repairs required.

Read Full Q/A … : I am getting horrible gas mileage.

Car gets very low gas mileage

ANSWER : I would do a little quick research and find out what is typical real-world MPG for others who drive your make and model. That will provide you a realistic base-line expectation that will be more accurate that Mazda or EPA estimates. Now to a few things that can hurt fuel mileage. The wind resistance from the rack will certainly make a difference. But more at highways speeds and less so around town at lower speeds. Tire inflation is a factor. Check them monthly and inflate as per door sticker. Your right foot is probably the biggest variable in all of this.

You could do an experiment! For one week drive like there is an egg between your right foot and the gas pedal. Your mission is to press very gently on the pedal so you don’t break the egg! The results will indicate if your poor gas mileage is due to "enthusiastic" driving. I don’t know if your Mazda has an automatic or manual transmission. If you have a stick shift and you regularly run it up to higher rpm’s before shifting, that will use more gas. If I was looking at scan tool data for an engine performance problem that was hurting gas mileage, I would view fuel trims and misfire data after checking for diagnostic trouble codes (DTC’s). If you would like to have this checked, a certified technician from YourMechanic can come to your home or office to diagnose the mileage issue.

Read Full Q/A … : I am getting horrible gas mileage.

When refilling gas tank, gas overflows before tank is full.

ANSWER : The most common cause of this type of problem is when the fuel filler neck’s inner tube comes off of the neck itself. You will need to have the filler neck removed to check to see if the inner tube was knocked off from someone trying to get fuel out of tank with a siphon hose and managed to knock the hose off. This causes the tank to not get filled properly and the inner hose can get caught in the fuel sender causing wrong readings.

If you’d like to get this fixed, consider YourMechanic, as a certified technician can help you service your fuel filler neck and ensure that your fuel gauge functions normally. Good luck.

Read Full Q/A … : I am getting horrible gas mileage.

Low gas mileage on 1997 GMC K1500 Suburban V8-5.7L

ANSWER : Hello. We will be happy to help with your 1997 GMC K1500 Suburban. There’s likely a combination of reasons as to why your MPG has so greatly declined. I suggest that you have a technician inspect the following items and perform the needed repairs.

Flush out the fuel injectors using an injector flush kit, replace your fuel filter, inspect the spark plugs and wires (and replace if necessary), check the air filter (replace if found dirty). Cleaning a dirty mass airflow sensor will help increase the MPG as well. I also suggest that you check the pressure and condition of the tires. Low air pressure or bad tires will decrease in MPG, too. If you would like to have this inspected by a professional, a qualified technician from YourMechanic can come to your car’s location to diagnose your mileage issue and let you know what should be done.

Read Full Q/A … : I am getting horrible gas mileage.