I have a 2003 Subaru Legacy Outback and just recently it started dying whenever I shift into reverse.

I am able to shift and backup for a bit but then it dies and I have to put it in park and turn off/start again. It is working fine in drive. I had the head gaskets and power steering pump replaced within the last two months. Brought it into the shop to bleed the PS pump more + get codes from a check engine light and the mechanic said it could be either an plugged fuel filter or exhaust leak. Check engine light has not gone on since the reverse stopped working. Any thoughts? Thanks

My car has 134000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hi There,
While this could certainly be caused by a fuel delivery problem such as a clogged fuel filter, it would seem odd that the same reaction would not happen in drive and only in reverse. The the fuel supply is indifferent to whether the car is in reverse or drive, this would seem to indicate potentially also something to do with the car’s response to a load put on the engine. I would recommend checking the MAP sensor to be sure it is working properly. Since the MAP sensor helps to contribute part of the information used by the computer to make air/fuel mixture changes, it may be possible that if this is not working properly, this may also cause excess emissions problems as indicated by your mechanic’s suggestion about an exhaust leak. I would recommend having the MAP sensor checked along with the fuel pressure as it sounds like this is definitely a fuel supply issue.

How to Identify and Fix Common car Problems ?

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

Common reasons for this to happen:

Low fuel pressure, dirty or defective fuel injectors, or broken fuel pump: The fuel pump is responsible for transferring fuel from the tank to the engine.

Defective fuel pump or filter: Since the fuel pump is responsible for supplying your vehicle with fuel, it can cause a loss of power when it begins to wear out or when the in-tank filter becomes clogged and prevents the free flow of fuel.
The most common reasons a Subaru Legacy won`t start are a dead battery, an alternator problem, or failed starter. Search our network of RepairPal Certified shops near you to speak with a technician about your issue.
Airflow sensor: When your airflow sensor is failing or dirty, it can send wrong signals to your engine`s computer that can result in power losses while accelerating. This type of issue usually causes your Check Engine” light to come on and your vehicle to behave sluggishly even when there is power.
Engines usually stop suddenly only if they suffer from a lack of fuel or sparks . An engine that stops dead without prior warning has probably had a sudden ignition failure – although if it locks solid it`s more likely to have seized.
The most likely issue is a clogged fuel filter. The purpose of the fuel filter is to ensure that dirt and debris stay out of the fuel system, so over time, it may need cleaned or replaced. When the fuel filter is clogged, the fuel pump has to work much harder, resulting in a far less efficient drive.
The top reasons why your Subaru may stall include a dirty air filter, a bad fuel pump, a faulty ignition system, clogged fuel injectors, a dirty throttle body, and a faulty mass airflow sensor. To prevent stalling, it`s important to have your car regularly maintained and inspected by a professional.
If your vehicle won`t start, it`s usually caused by a dying or dead battery, loose or corroded connection cables, a bad alternator or an issue with the starter. It can be hard to determine if you`re dealing with a battery or an alternator problem.
An engine that is hesitating to accelerate is most likely dealing with a fuel/air mixture that is too lean. Engine`s that are running inefficiently will begin to show signs like hesitation which will only become worse over time.
It could be a dead alternator, a bad coolant sensor or lack of fuel, just to name a few. Is your car stalling while accelerating? If so, then it could be a major vacuum leak, clogged fuel filter or a bad fuel pump. If your vehicle is stalling when driving, seek professional help to track down and fix the issue.
Faulty Battery

A classic reason why your car starts for a second then dies is battery depletion. The car needs electricity from the battery to start. However, if your car starts then dies immediately, then the fault could be a lack of charging or damaged battery.

For the matter of “how long do Subarus last,” you can expect to reach around 200,000 to 250,000 miles on your trusty Subaru. Furthermore, Subarus can last up to 10-13 years before requiring a significant amount of work to keep them on the road.
Generally speaking, a Subaru 2.5 engine has the ability to run between 250,000 and 300,000 miles before needing any kind of significant auto maintenance or repair. Since most drivers average around 14,000 miles per year, this would mean that a Subaru 2.5 engine could conceivably run for over two decades.
Although Subaru has been challenged with engine issues, most of the issues were isolated to a few engines, namely the EJs that were in the Impreza, Forester, Legacy, Outback and Baja models between 1996 and 2005. The latest Subaru boxer engines are part of the FB series boxer engines.
Subaru has acknowledged that its front O2 may be defective and issued a recall for various models, including 1998, 2000-2007, and 2009-2014. Air conditioning (A/C) failure: A/C problems are common among Forester model years. Owners reported the hot air from their vehicles, eventually leading to a faulty A/C.
Typically, a vehicle will start and then quit because of an issue with the fuel or electrical system. It is important to monitor fuel levels as well as warning lights which can signal to the driver that a vehicle may quit unexpectedly.
Bad Sensors

One common culprit for this problem is the crankshaft position sensor, which measures the position and speed of the crankshaft. The computer uses the information from this sensor to know when to fire the spark plugs. If the sensor isn`t working, the spark plugs won`t fire, keeping the engine from starting.

Defective ignition switch

If you know your battery is working properly, but your car doesn`t turn over on the first few tries, you might have a problem with the ignition switch. You can try to narrow down the cause of your issue by turning on your headlights.

The easiest way to perform an ECU reset is by removing the fuse from the fuse box. It is a very simple process, and all you have to do is pull out the car key, remove the fuse from the fuse box, and then put it back after about 15 to 20 seconds. Doing this clears any long-term memory stored in the car`s ECU.
Disconnecting your battery and draining the power to cause an ECU reset is one of the most common fixes for a check engine light that won`t go away on its own. Doing so is equivalent to a hard reboot on a desktop computer, which is a standard way to eliminate many common problems.
The Subaru EJ25 2.5-liter Boxer is the engine that has experienced the most problems for the Japanese automaker. The gasket material they used in this engine was unreliable and Subaru attempted to correct the issue in 1999 with an updated multilayered metal shim gasket. But some 2001-2009 engines still had the problem.
Lack of lubrication: The most common cause of engine failure is dirty or low oil, which can be the result of an oil leak, faulty oil pump, the oil burning too fast, or driving too long in between oil changes.
Airflow sensor: When your airflow sensor is failing or dirty, it can send wrong signals to your engine`s computer that can result in power losses while accelerating. This type of issue usually causes your Check Engine” light to come on and your vehicle to behave sluggishly even when there is power.
You will feel a loss in power while accelerating and at times intermittent jerks. To solve this issue find the fuel filter located in the engine bay or near the fuel tank in your car`s trunk. If the fuel filter is clogged replace it if you have the skills to do so or get it changed at your local mechanic shop.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

I have a 2003 Subaru Legacy Outback and just recently it started dying whenever I shift into reverse.
ANSWER : Hi There,
While this could certainly be caused by a fuel delivery problem such as a clogged fuel filter, it would seem odd that the same reaction would not happen in drive and only in reverse. The the fuel supply is indifferent to whether the car is in reverse or drive, this would seem to indicate potentially also something to do with the car’s response to a load put on the engine. I would recommend checking the MAP sensor to be sure it is working properly. Since the MAP sensor helps to contribute part of the information used by the computer to make air/fuel mixture changes, it may be possible that if this is not working properly, this may also cause excess emissions problems as indicated by your mechanic’s suggestion about an exhaust leak. I would recommend having the MAP sensor checked along with the fuel pressure as it sounds like this is definitely a fuel supply issue.

My truck died while driving. Now will start, but dies when I push brake. If I start in neutral, I can put in drive and go but dies – 2003 Ford F250
ANSWER : Hello – your symptoms suggest that once your cold start features are no longer needed – engine warming up – there is an air "leak" that ruins low speed running. Causes could be a leaking exhaust gas recirculation (EGR) valve, or leak in the air intake. A failing fuel pump relay (burned contacts) could cause similar behavior, contacts become hot, then won’t pass enough current to run the pump. Failing pump can also act this way – gets hot and fails. I recommend a starts, then dies inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

Cranks over start than dies
ANSWER : Hi There,
The idle air control valve is a small valve on the engine’s intake system that reads the air intake as it comes into the motor. This is controlled by the car’s ECM which uses this information to make adjustments to the air/fuel ratio depending on various inputs such as outside air temperature, intake air temperature, load and various other things. As you accelerate, your car’s engine is receiving a much higher dose of fuel than when at idle and conversely, when you let off the gas pedal, there is a sudden change in this fuel supply as a result of your foot letting off the pedal. When this happens, the job of the idle air control valve is to bring this deceleration down to a slow and smooth idle rather than suddenly cutting off the fuel supply causing the motor to die. When the idle air control valve is not working properly, this cause a disruption in this process resulting in the engine not being able to idle properly. I would recommend having a professional come to your location to diagnose and inspect your vehicle.

My pacifica runs and drives only reverse when i shift it to drive dies quickly . But you can shift it to reverse and neutral
ANSWER : This is an internal problem with the transmission and may be a valve body or leaking internal seal. The problem is the transmission leaking pressure internally, and when you put it in drive, the transmission is trying to go into reverse and drive at the same time causing the transmission to stall the engine. Have a mechanic, such as one from YourMechanic, scan the computer to see if a code is received that will help detect the cause. They will be able to diagnose your stalling issue, and any other problem you are having, so that a proper repair can be made.

Fuel pump engages. Batery good, alternator good volts, jump start helps when wont start. Temp does not matter. Intermittent?
ANSWER : Hello. Thank you for writing in. There are several reasons your vehicle may only start when jump starting. The first and most common is a build up of resistance that is causing you to need a boost of voltage to get the engine started. This may be due to poor battery cables, a bad ground connection, a poor starter solenoid, and a couple of other issues. The first thing you want to do is perform a visual inspection of the starting system. Make sure there is no corrosion build up in the battery cables. You can also check the resistance across these wires and make sure you have a solid connection between components. You then want to make sure the starter solenoid is doing its job. It is responsible for taking the small amount of electricity sent by the ignition and turning it into a huge electrical charge that is strong enough to push over the engine with the help of some gear ratios in its favor. Do some more testing, and stick to the basics before assuming its something seriously complicated.

Car started shaking. Cleaned carb and air filter. Now it starts, runs, dies, or starts and dies.
ANSWER : Hello. The stalling issues you are having may by caused by a variety of issues. Typically these symptoms can be blamed on fuel, spark, or air. Fuel and spark being the most common systems to fail. Starting with the air filter and cleaning the carburetor were good steps to start. You need to take a better look at the spark system. The spark wires can be tested to make sure the plugs are receiving the voltage that they need to be. You can also test the fuel system by spraying some starter fluid into the air intake. If this helps the engine start and run better than before, then you know you have a fuel delivery issue. This may include the fuel pump, fuel filter, injectors, or a clogged fuel line. The shaking is due to the improper combustion happening in the engine. This will be corrected when the engine is running properly. More testing is the only way to know definitively what the issue is.

Wont start (Click), shift gear from P to R then back to P Starts it, after runs for a while it starts up fine.
ANSWER : Your vehicle has something called a neutral safety switch that will prevent the vehicle from starting when it is in any gear position other than park or neutral. Occasionally, this switch can malfunction causing the car to stall as soon as you put it into any gear. This switch usually also monitors gear selection data as well to transmit back to the computer. This switch is connected to the starter solenoid which allows it to complete the starter circuit only when the transmission is in park or neutral. I would suggest having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

I changed the fuel pump and truck ran great for 3 days. Now after 3 days, the truck dies. It will start running for a few minutes, then dies like before.
ANSWER : Hi there, thanks for writing in. I’d be happy to help. It sounds like you should disconnect the connector to the fuel pump and inspect it for any signs of getting hot. The female connections may be too loose on the fuel pump and lose contact after running and getting hot. If there are indeed any signs of problems, then I’d suggest replacing connector and adding dielectric lube to pins before installation. This should solve the problem, but if you continue to experience issues, feel free to reach out to us for help again.