jemcdon Posted April 15, 2012 Share Posted April 15, 2012 Hi, I've a 2001 Subaru Legacy Outback with Manual Transmission and 2.5 litre engine. I do not have any turbo and have made no modifications to any of the components. I have about 85K miles on the car. I've experienced two issues with a loss of power and rough idling that resolved themselves after a few minutes. Both times the check engine did not come on. The first instance happened after a rapid deceleration (with less than 1/4 tank of gas), the engine lost power and recovered after about 5 minutes. This happened in the fall 2011. Recently after sitting in a parking garage for about 4 hours on a slight decline toward the front of the car. Again, the engine recovered and has been running well since the problem. In the first instance, I took it the subaru shop for help. They indicated that they couldn't do much if the check engine light didn't come on but rationalized that I likely had water in the fuel tank--since I had less gas in the tank during that incident. So I treated the tank with heet. In the recent instance I had more than 1/2 tank of gas, so I don't think water is a likely reason for the issue. The car was parked on a decline, but I've been parking on the same decline for two years without an incident like this. I've recently tuned up the car with new wires and plugs and I also have recently replaced the fuel filter. (The first incident occurred before these items were replaced.) Any ideas as to what could be the issue? Regards, Jeff Link to comment Share on other sites More sharing options...
Legacy777 Posted April 17, 2012 Share Posted April 17, 2012 Welcome to the USMB Jeff. Unfortunately, intermittent issues like this can be rather difficult to troubleshoot. I had an issue on my 90 Legacy several years ago where I would lose power in the engine while driving. Sometimes if I was cruising along I could put the trans in neutral and try and rev the engine back. Other times if the rpms were low, the car would just die. I had this issue for over a year. It eventually acted up worse, where the car wouldn't start for a few minutes. It however left a code for the MAF sensor. I ended up replacing the MAF sensor and that fixed my issues. I can't say for sure whether the MAF sensor is your problem, but what I would suggest is if you know someone with a similar subie with the same MAF sensor or if you can find a cheap MAF sensor at a junkyard, to swap it and see if that helps. You may just have to monitor things for a while until it gets worse or until you get a code. I know that's probably not ideal, but otherwise, you're just throwing parts at it, and that can get expensive. Link to comment Share on other sites More sharing options...
nipper Posted April 17, 2012 Share Posted April 17, 2012 Hi, I've a 2001 Subaru Legacy Outback with Manual Transmission and 2.5 litre engine. I do not have any turbo and have made no modifications to any of the components. I have about 85K miles on the car. I've experienced two issues with a loss of power and rough idling that resolved themselves after a few minutes. Both times the check engine did not come on. The first instance happened after a rapid deceleration (with less than 1/4 tank of gas), the engine lost power and recovered after about 5 minutes. This happened in the fall 2011. Recently after sitting in a parking garage for about 4 hours on a slight decline toward the front of the car. Again, the engine recovered and has been running well since the problem. In the first instance, I took it the subaru shop for help. They indicated that they couldn't do much if the check engine light didn't come on but rationalized that I likely had water in the fuel tank--since I had less gas in the tank during that incident. So I treated the tank with heet. In the recent instance I had more than 1/2 tank of gas, so I don't think water is a likely reason for the issue. The car was parked on a decline, but I've been parking on the same decline for two years without an incident like this. I've recently tuned up the car with new wires and plugs and I also have recently replaced the fuel filter. (The first incident occurred before these items were replaced.) Any ideas as to what could be the issue? Regards, Jeff Find another shop. Be thankful they did not work on your car, as only a lazy or poorly skilled shop would just rely on the CEL alone. Your mileage is low so it is a bit goofy to find out. Replace your PCV valve, as they can cause goofy issues. Possabilities is a sticking Idle control valve or a flacky knock sensor. was the car hot or cold when it happened. Link to comment Share on other sites More sharing options...
jemcdon Posted April 18, 2012 Author Share Posted April 18, 2012 (edited) Hi Legacy777, I don't have a MAF sensor in the 2001 Outback. Is the MAP sensor equivalent? I purposely ran the gas very low today and I had another event with the same issue. Eventually the car actually cut-out. It was running very rough at low RPMs and better at higher RPMs. A car in front of me turned and I shifted out to neutral, once the rpm went low and the car shut-off. I was able to immediately re-start it and it ran better. I filled up at the gas station and then purchased a water removal gas treatment again. The engine seems to be running fine now. This event also did not result in a check-engine light coming on. I can't very well understand the second event when the car was cold and parked for four hours as water in the fuel tank since I had 1/2 tank of gas. This was the third event and two of them happened when I had a low tank of gas and the engine was warm. How many treatments would I expect to need if I have some water in the fuel tank? I've had lots of bad experience with mechanics, so I'd prefer to check it out myself. I'm going to borrow an OBD reader and see what I find. Regards, Jeff Edited April 18, 2012 by jemcdon Link to comment Share on other sites More sharing options...
nipper Posted April 18, 2012 Share Posted April 18, 2012 Stop with the water treatment already. There is no water in your tank, period. If you have ethanol in your gas already it is the same thing. Do me a favor, loosen your gas cap and run it down. Lets see if it is a venting issue. Link to comment Share on other sites More sharing options...
jemcdon Posted April 18, 2012 Author Share Posted April 18, 2012 Hi Nipper, Thanks for the response. I'm not following exactly what you want me to do... Do you want me let the gas run down, then try to vent the tank by removing the cap if it has idling problems? regards, jeff Link to comment Share on other sites More sharing options...
nipper Posted April 18, 2012 Share Posted April 18, 2012 Well since it is an intermittent problem it will be tough. I am thinking the gas cap is bad or something in the evap system. The evap puge valve is activated when the car is started for a few seconds. This might be why on restart it starts fine. What happens if you fill the tank at 1/2 for a few times in a row. I think the angle of the car may just be a fluke. It sounds like a fuel delivery issue to me now. Link to comment Share on other sites More sharing options...
ferret Posted April 18, 2012 Share Posted April 18, 2012 You are in the year range for some front O2 sensors that act up. I have seen MANY of these since 2002 even to the point an Outback wouldn't even start and was flatbedded to the dealer only to start there. Does it do it AFTER warmup? If so this is the start of the front o2 symptoms diagnoses. If you can, when it's acting up, shut off the engine. Open the hood and on the passenger rear side by the firewall, reach down and unplug the front o2 sensor ( THIS WILL SET A CHECK ENGINE CODE ). Now start the vehicle and drive it to see of the bucking had stopped. ( It WILL run, you are in open loop mode and running on a set of predetermined fuel mixture parameters ). If the bucking STOPS, chances are you have a defective front sensor. If it continues, the front sensor is NOT the problem. Either way you now have to reset the Check engine light, but have done at least 1 valid check for your problem. This certain run of sensors ( 2001 to 2004 various models ), after warmup intermittently indicate the exhaust is RICH. In turn the ECU leans out or shuts down the fuel injectors until the sensor reads nothing. I mapped one years ago while trying to diagnose my first one of these. Then you have to determine, " is this the Cause, or the Effect of something else". Link to comment Share on other sites More sharing options...
ferret Posted April 18, 2012 Share Posted April 18, 2012 After re-reading the first post, do you have loss of power while driving? If so my post above still stands. Or do you have an Idle problem after running, but the car runs fine at highway speeds? Different problem. Link to comment Share on other sites More sharing options...
jemcdon Posted April 18, 2012 Author Share Posted April 18, 2012 (edited) Hi Ferret, Things are getting worse. I've had a fourth event this morning after a cold start. Finally the check engine light came on so I should have a code now. This is the fourth event, two happened when the car was hot and two have now happened after a cold start. After the check engine light came on, the car ran better so I don't know if it ignores the sensor after that..... So, thats two events that happened after being warm, two events after being cold. Twice it happened when the fuel tank was less than 1/8 of a tank, once it happened with 1/2 tank of gas and this morning the tank is full of gas and it happened. regards, jeff Edited April 18, 2012 by jemcdon Link to comment Share on other sites More sharing options...
ferret Posted April 18, 2012 Share Posted April 18, 2012 Is this a problem at idle or at speed? Link to comment Share on other sites More sharing options...
nipper Posted April 18, 2012 Share Posted April 18, 2012 I am going between the IAC vavle and the gas cap. Ever smell fuel? I know Blu was acting odd when gas got low and a new cap solved it, but I also smelled gas sometimes. Link to comment Share on other sites More sharing options...
ivans imports Posted April 18, 2012 Share Posted April 18, 2012 Have had a bunch with water colecting in gas tank it finds the low spot at pickup and whont pull thrugh pump very intermitant try some methel hydrate or feul pump had some in cold whether that water got in pump and froze pump still worked but poorly and cars ran lean Link to comment Share on other sites More sharing options...
nipper Posted April 18, 2012 Share Posted April 18, 2012 Not the issue, and if you use it too many times when the fuel is low you can start damaging fuel system parts. Link to comment Share on other sites More sharing options...
Legacy777 Posted April 18, 2012 Share Posted April 18, 2012 Since there's a code stored, check the codes and see what it points to. No sense is trying to guess. Link to comment Share on other sites More sharing options...
dburdick Posted April 18, 2012 Share Posted April 18, 2012 I am following this thread because it sounds similar to what I am dealing with. I have a 2000 Outback and 4 days ago it started cutting out (feels like bucking) mainly when I try and speed up. It helps to floor the car, but that is the only thing that makes it better. At the next light it will do the same issue unless I floor it. It seems okay at highway speeds. I think it may still do it slightly even at highway speeds only when I lightly step on the gas, but if it does it's so slight that I can hardly tell there is an issue. This is an intermittent issue, so it does not do it all the time. My check engine light is not on. I did just replace a knock sensor due to a check engine light, but the light has not come back on. I also thought it might be a gas cap issue, so I opened the gas tank up and it still did the issue right away. I may still replace the gas cap just in case. I will also unhook the o2 sensor as someone else suggested just to rule that out. I also put a gas cleaner in a couple days ago, but that did nothing. Maybe a fuel filter? I will post if I figure it out. Link to comment Share on other sites More sharing options...
jemcdon Posted April 18, 2012 Author Share Posted April 18, 2012 Sigh.....this morning, the car was idling rough and bucking. At one point about 1/4 mile from my house, I saw the 'check engine' flash for 5-10 seconds. After the 5-10 seconds of flashing check engine, the entire system got better and I didn't experience any more issues today. I thought that a code would be recorded....but it wasn't....I tried to read it with an ODB2 reader which said there were no codes. I'm reluctant to think that it can be a O2 sensor or other sensors which are monitored but rather something outside the scope of the monitoring/reporting system. Responses to other questions: 1- I never smell gas 2- the engine runs poorly both at speed and idling. At speed, I experience bucking and a loss of power. The issues happen for a short period of time and the system recovers. regards, jeff Link to comment Share on other sites More sharing options...
ferret Posted April 19, 2012 Share Posted April 19, 2012 When it idles rough, does the exhaust smell REALLY BAD ? Link to comment Share on other sites More sharing options...
jemcdon Posted April 19, 2012 Author Share Posted April 19, 2012 No, I didn't smell any 'rich' exhaust. jeff Link to comment Share on other sites More sharing options...
Caboobaroo Posted April 19, 2012 Share Posted April 19, 2012 Ok, a flashing check engine means there is a cylinder misfire. Should have a code like P0300 (multiple cylinder misfire), P0301, P0302, P0303, or P0304 which is a specific cylinder misfire (cylinder 1, 2, 3, 4). It will help us further diagnose the issue to know the code though. Now it is a known issue that the coil pack terminals corrode inside the ends of the spark plug wires. Since the coil pack is right on top, start by disconnecting one at a time, looking for any signs of corrosion. It's a common issue, I actually had the end break off of one a few days ago while I was checking them. If it turns out to be the issue, sometimes the coil pack can be saved but other times, the corrosion gets so bad it eats the terminal and doesn't give you a good connection. I use red scotch brite to clean up the terminals before I put new plug wires on. It will not kick on a check engine light unless the corrosion is bad enough but it can lead to run ability issues. Link to comment Share on other sites More sharing options...
ferret Posted April 19, 2012 Share Posted April 19, 2012 not rich, but just plain bad ..... does your 01 have an EGR? Link to comment Share on other sites More sharing options...
jemcdon Posted April 19, 2012 Author Share Posted April 19, 2012 EGRs didn't show up until 2003 models, so I don't have an EGR. I didn't notice any unusual smell from the exhaust. jeff Link to comment Share on other sites More sharing options...
dburdick Posted April 19, 2012 Share Posted April 19, 2012 Same issue as jemcdon. I don't have strange gas smell either and my issue is at idle & especially when I am speeding up (its rough and bucking). I started thinking it was the new knock sensor I put in, so I put the old one in (since the old one did not have this issue). The issue still occurs, so it's not that...it just so happens that my issue started 1 day after the knock sensor replacement and it's not associated. I also unplugged the o2 sensor as someone suggested, but the issue still occurs. I also tried to loosen the gas cap and run it, but that did not help. Only difference from jemcdon so far is that I have not gotten the check engine light to come on at all (until putting bad knock sensor back in and unplugging the o2 sensor). I will check my terminals tonight as Caboobaroo suggested. Link to comment Share on other sites More sharing options...
dburdick Posted April 19, 2012 Share Posted April 19, 2012 Terminals look fine. I am going to clean the IAC tonight and replace the PCV. I will post back if anything works. Link to comment Share on other sites More sharing options...
jemcdon Posted April 21, 2012 Author Share Posted April 21, 2012 I replaced the PCV yesterday and I have the IAC solenoid-valve off today and cleaning it. The IAC valve was covered in grime. jeff Link to comment Share on other sites More sharing options...
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