2001 Outback 6 Losing its Oomph



My 2001 Subaru LL Bean Outback has 103K miles and has been well maintained. Lately, however, it has lost its usual “get-up-and-go” (not that it ever was the peppiest horse in the barn). It was also running a little roughly. The dealer soaked me for a #6 fuel injector replacement as a cure for the problem. It is running more smoothly, but it still feels sluggish. My wife loves this car but is disappointed that it has lost its vigor. Suggestions?


Did the check engine light come on when it was running rough? What were the codes? How did the dealer diagnose a bad injector?

Does it need new spark plugs? A new fuel filter? Is the transmission fluid at the correct level and clean? Could the parking brake be dragging? Are the tires correctly inflated and is the wheel alignment correct? Are you carrying lots of extra stuff in the car? Is the engine reaching and maintaining the correct operating temperature? Is the air filter clean?

Lots of things could contribute to a lack of power, or a perceived lack of power.


Thanks for your reply. We did all of that stuff. Plugs, wires and filters are new. Trans was fully serviced including dropping the pan. Tires are relatively new and properly inflated. My wife keeps the car empty since she hates to have junk rattling around. I do not know the codes (I wish I had asked).


Oh yeah, engine temp seems OK.


This car has a 6 cylinder engine, right? Does it require premium fuel? If so, are you using premium? The use of regular gas in an engine that needs premium will result in reduced power.

Ethanol blended fuels also reduce power and fuel mileage. Have they added ethanol to the gas you buy?


Quote: “not that it ever was the peppiest horse in the barn”

Your engine may have been problematic from the beginning, as these engines are powerful and few cars can keep up with them once you hit 3,000 rpm. (Trust me–I know since the only vehicle that ever out-accelerated my '02 VDC (same engine as yours) was a Harley-Davidson).

That being said, I also question whether you have been using the recommended premium gas, as it does make a significant difference with this engine. Another thing that might be checked is the catalytic converter. If it is clogged, that might account for a lack of pep.


If it’s running roughly there may be misfire. The engine computer will “forgive” a certain amount of misfire and NOT set a DTC (Diagnostic Trouble Code). Thus, NOT turn on the check engine light (or, symbol). Sufficient misfire will set a DTC of P0300 through P0306; and, maybe P0313, or P0314. Weak spark, or a fuel system, or an etc. system, can cause misfire. Many large auto parts stores will scan the engine for free if the check engine light is on. What would be very helpful when the scan is done, is to get the FREEZE FRAME data, also. This would tell us some of the conditions, shown by the engine sensors, when the DTC was set in the engine computer.// Knowledge is…Useful.


Thanks for all the responses. I have always used premium fuel (it calls for 91 octane, but most stations only sell 93 around here). I do recall it feeling much more powerful when it was younger. I will have the cat converter checked. My local indie mechanic doesn’t like to work on it (engine compartment too tight), so I am frequently at the mercy of the dealer (about whom I have some doubts). I am thinking of taking it to another dealer just for a fresh look.


The roughness has gone away and the check engine light is not on. Is there any way to get old codes out of the computer? Maybe my dealer has a record of them in the service file.


I think ethanol is blended into gas around here.


Often the light may go out, but the codes will still be there. Most anyone can read them. Some places like Autozone and Advanced Auto Parts will do it for free.


Since information is …useful, let’s try to get some more. Call a (some) local automotive parts stores. Ask them if they do the free engine computer scan. If they say, “Yes”, ask them if they know how (and, will) pull the FREEZE FRAME data. If they don’t know what you are talking about, or, say, “No”. Try another store. This isn’t hard. It’s just a press of an FF button on the scanner. /// Your task is to take the car to the participating store; turn the ignition key off; disconnect one of the sensors on the engine (It doesn’t matter which). This action will set a DTC (Diagnostic Trouble Code) in the engine computer, AND the freeze frame data will be recorded by the computer. /// All set? When the scanner is connected, start (or attempt) the engine (the sensor should STILL be disconnected). Turn the ignition OFF, and, then, to RUN. Use the scanner to take the DTC and the FREEZE FRAME data./// Bring all that information here. One of the ace mechanics will read the results, and give you further advice. //// It sounds a lot more complicated than it actually is.


I think a compression test is in order.


check spark plugs/wires


I would check for a clogged catalytic converter. The previous running rough could have contributed to any clogging.

It’s also easy to test for a clogged cat. Simply connect a vacuum gauge to the intake and see what happens.
Unfortunately many mechanics don’t use a vacuum gauge for some reason and it’s a shame; they can tell someone so much about what’s going on in that engine.


Well, that could account for everything. Ethanol reduces horsepower and fuel mileage. Nice, isn’t it? Ethanol is a scam, pure and simple. It doesn’t save any energy. It takes more energy to produce ethanol than there is in the ethanol produced.

Try to find a gas station that does not have ethanol in its blend. Try a few tankfuls and see if it makes a difference.