740gle Posted July 9, 2007 Share Posted July 9, 2007 Both my wife and I noticed a lack of usual power in our 02' Legacy GT (non-turbo). It is definitely slower when merging in traffic and off the line. It feels like it flattens out or even drops the acceleration above 3000 rpm's I have just changed oil and filter, and air filter. Spark plugs and wires where replaced a year ago or so, with the OEM parts. Where do I look for? No OBDII codes. Mileage is as usual, or even somewhat better, no strange noises, no visible oil in the coolant, and no visible coolant in the oil. If it was manual transmission, I'd suspect slipping clutch, it feels similar. Can it be something slipping in AT, or AWD ? It does have some exhaust leak, but I am not sure it may be related to the power loss ? -Michael 02' Legacy GT wagon 101Kmiles Link to comment Share on other sites More sharing options...
zstalker Posted July 9, 2007 Share Posted July 9, 2007 without looking into diagnosis, you didn't mention your fuel filter has been changed recently. change it. it takes like 5 minutes with a phillips screwdriver. a clogged fuel filter will start starving the engine at higher RPM, just like you say is happening. even if this doesn't immediately solve your loss of power, it's certainly a good thing to do. ~Erik~ Link to comment Share on other sites More sharing options...
740gle Posted July 9, 2007 Author Share Posted July 9, 2007 without looking into diagnosis, you didn't mention your fuel filter has been changed recently. change it. it takes like 5 minutes with a phillips screwdriver. a clogged fuel filter will start starving the engine at higher RPM, just like you say is happening. even if this doesn't immediately solve your loss of power, it's certainly a good thing to do.~Erik~ Fuel filter and transmission fluid were replaced last summer (10K miles ago) by the dealer as part of the 90Kmiles service. I've seen a fuel filter under the hood, and it doesn't seem to be a difficult job to replace it, although, I've never did anything on the fuel system. How do you relieve the fuel pressure? -Michael Link to comment Share on other sites More sharing options...
nipper Posted July 9, 2007 Share Posted July 9, 2007 Sounds like you may have a clogged catalytic converter. nipper Link to comment Share on other sites More sharing options...
OB99W Posted July 9, 2007 Share Posted July 9, 2007 Fuel filter and transmission fluid were replaced last summer (10K miles ago) by the dealer as part of the 90Kmiles service.Not to be cynical, but did you get the old parts back? I've seen a fuel filter under the hood, and it doesn't seem to be a difficult job to replace it, although, I've never did anything on the fuel system. How do you relieve the fuel pressure?You might find these of interest:http://endwrench.com/images/pdfs/Fuel.pdf http://endwrench.com/images/pdfs/07FebFuelEW.pdf Possible exhaust restrictions can be tested for with a vacuum gauge. Link to comment Share on other sites More sharing options...
740gle Posted July 9, 2007 Author Share Posted July 9, 2007 Not to be cynical, but did you get the old parts back? No, they never do.... I've been going to them since we've got the car. The fuel filter doesn't look like it's very old anyways. I am doing oil changes and simple tuneup (wires, spark plugs) myself, though. You might find these of interest: http://endwrench.com/images/pdfs/Fuel.pdf http://endwrench.com/images/pdfs/07FebFuelEW.pdf Thanks, Possible exhaust restrictions can be tested for with a vacuum gauge. Details or references would be very much appreciated. -Michael Link to comment Share on other sites More sharing options...
idosubaru Posted July 9, 2007 Share Posted July 9, 2007 does the transmission shift fine or seem to lag sometimes too? Link to comment Share on other sites More sharing options...
OB99W Posted July 9, 2007 Share Posted July 9, 2007 Details or references would be very much appreciated. If you don't already own a vacuum gauge, a perfectly adequate one (it doesn't have to be fancy) can be purchased for about $20, and sometimes even less. Start by thoroughly warming the engine. Connect the gauge as in the link below. Determine the initial idle vacuum reading -- a healthy Subaru N/A typically reads over 20 inches at idle, and is pretty steady. To test for exhaust restriction, bring the engine speed to 2000-2500 RPM, and hold it there for several (10-15)seconds. The vacuum should remain relatively constant, not slowly drop towards zero. Click on Scenario 14 in the link; only a very plugged exhaust would cause the gauge to actually reach zero, but partial blockage will cause a noticeable drop. (The gauge demonstrated in the link moves counterclockwise with increasing vacuum, while some others have the opposite rotation. That doesn't matter, as long as attention is payed to the scale on the actual gauge being used.) I'm not anticipating other specific problems, but if you see a reading that wavers, rhythmically drops, etc., click on the other scenarios in the link to interpret it, and let us know what you find. Link for vacuum gauge reading interpretation: http://www.secondchancegarage.com/public/186.cfm Link to comment Share on other sites More sharing options...
OB99W Posted July 9, 2007 Share Posted July 9, 2007 By the way, just because the filter was changed 10k miles ago doesn't mean it can't be a fuel delivery problem. Sometimes you can just get a tank of gas that's contaminated, and the filter could be partially blocked no matter how new. Link to comment Share on other sites More sharing options...
SuBrat84 Posted July 9, 2007 Share Posted July 9, 2007 To relieve fuel system pressure you are supposed to disconnect your fuel pump power supply and then start your car and let it run until it dies. With the fuel pump not running it will suck the fuel out of the line but not through the pump. Have you check for vacuum leaks around the air box and tubes leading to the intake? Sometimes a vacuum line can come loose while changing the air filter and be over looked. Link to comment Share on other sites More sharing options...
OB99W Posted July 9, 2007 Share Posted July 9, 2007 To relieve fuel system pressure you are supposed to disconnect your fuel pump power supply and then start your car and let it run until it dies.[...]Yes, as detailed on page 10 (right column, near the top) of the link I previously mentioned above:http://endwrench.com/images/pdfs/Fuel.pdf Link to comment Share on other sites More sharing options...
740gle Posted July 10, 2007 Author Share Posted July 10, 2007 does the transmission shift fine or seem to lag sometimes too? Yes, it does. Link to comment Share on other sites More sharing options...
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