p.monro

Rough running at low revs is often caused by a vacuum leak. There may be no codes displayed. The leak is often in the hoses which, with an older car, have become cracked or split at their ends. In my 1991 legacy the leak occurred at the junction between the air inlet duct and the inlet manifold. I spent a lot of time looking for it but the agent found it real quick. I guess he put a vacuum gauge on the manifold to check for vacuum leak. You could try squirting oil over the various air inlet joints to see if this improves performance as this acts as a temporary seal. It is an old technique but personally I have not had much success with it.

Have you checked there is spark at the plugs. You can do this by hooking up a good plug and then cranking or running the motor whilst looking for spark. maybe the suggestion of the igniter by a previous writer is worth looking at

Your proposed oil squirting technique may work. I guess the idea is that it temporarily closes the small leak so that you can see if the engine runs better. You would need to be sure to cover the whole perimeter. Perhaps a thick grease may be better. If you had a vacuum gauge I would check the manifold vacuum. Haynes says it should be 425 to 550 mm (about 16 in) mercury and not fluctuate. If it is 10 to 25kpa (2in Hg) below normal and fluctuates at the low reading suspect an inlet manifold leak at an intake port. Haynes also gives a lot of other methods for diagnosis from the vacuum gauge reading.

Could it be that you have a vacuum leak at the gasket on the air intake on the passenger side. At idle, the vacuum is highest and so there would be too much air. This would give the impression of the car running the same with the injectors disconnected. At power the car would seem to run OK because the furl/air balance is more near the correct value. That is my guess at your problem

If you have checked the codes and there are none then I suspect that your idle problem is a vacuum leak. This lets too much air in at idle. At higher revs it is not so odvious because the vacuum is lower. It should also happen with the engine both hot and cold. The usual cause is cracked vacuum hoses but also the 2 air inlet manifold gaskets may be leaking

Yes I agree with Josh Depending on how the coolant temerature sensor fails . If after checking the codes you disconnect the battery for say 30 minutes this should reset the alarms. The fans may then not turn on at start depending on how the alarm is processed. My guess is that you have had the check engine light up sveral times and not taken any action so after say 5 or 10 such events the ECU has latched the fans up

When using the word "dip" I mean the action one takes by lowering the head light beam so as to provide better visibility to on coming traffic. The headlights are "dipped" by operating the lever provided for this purpose on the steering column. Do you use another word for this? If the lights appear to be dimmed this could be as a result of the dipping relay chattering as a result of poor voltage caused by an open joint or a short circuit

Interesting---- Few have commented on the radiator. I would have expected a failure of the plastic end cap by 200,000. However I note that many respondents come from colder climates so presumely this failure is temperature related. Failures are both distance and age related. My 91 legacy on 190,000 km plus is now starting to show age problems, rust and seal (air manifold gasket) failure. It and my 92 legacy have both had radiator end cap failure but nothing major

You are correct. Personally I think you are on the right track. Like you, I would concentrate on why the lights dim. I presume you mean dim (not dip). If the lights dip then this is an electronic problem similar to the tacho. But if the lights dim it is probably a power problem and should be more easily traced. I think you should look for either a short to earth that is enough to drop the electronic voltage but not enough to blow the fusable link. Somewhere between the battery and the ignition switch. or a dry joint Perhaps the ignition switch is the problem. I presume that on your vehicle the ignition switch also turns off the lights. A faulty switch explains all the problems you describe.

Maybe the flood water damaged one of the sensors and this is why the CE light is on. Go to this link and it will tell you how to find out which sensor is bringing you CE Light up http://www.surrealmirage.com/subaru/subaru.html

You don't say what maintenance you have done. Chances are that like me you dont do anything until a problem occurs. So start with a bit of a clean up, plugs, ignition wire clean and inspect, battery check, clean air filter

The next thing to do is check the codes. Josh (legacy777) has a web site with the procedure which I presume works with an outback. Have a look round this forum for the link to his site and previous enquiries about reading codes. The legacy will run satisfactorily with some of its tranducers out of spec but eventually,when they get too far out, performance will suffer.

My daughters 2.2 Legacy had idle problems hot and cold but there were no alarms. I checked the Haynes manual and did all the recomended things like plugs, air filter, clean throttle body, check for vacuum leaks. I also tried to remove the Iac valve but gave up because of the difficulty. However the Iac valve did not seem likely because it is supposed to to be closed when hot and I simulated that by pinching the hose. All that did was stall the car. So in the end I gave up and sent it to the dealer who fixed it quick. Vacuum leak on the inlet manifols gaskets. He replaced two of them.

You need to check the codes as Josh says. A faulty temperature sensor can bring up intermittent check engine light. In my case it occured about 5 minutes after start up and was up for about 3 minutes. However when I checked the resistance of the sensor it appeared to be within specification. This went on for about 6 months before it finally caused a problem by latching up all the radiator fans. Perhaps this is the cause of your rough idling also. It is one of the transducers that causes hard starting. Regards Peter

I would back the hairline crack in the radiator end cap. These caps are made of plastic and is a usual cause of loss of water from the radiator. When the radiator pressure rises the crack opens a very small amount to discharge water and when the pressure is relieved the crack closes. The closed crack is almost impossible to detect visaully. You can perhaps get an indication of the leak be observing if the bottom of the radiator is moist. It can be tested by filling the radiator and then running the car to raise the pressure but you will need to look in the correct spot at the time it discharges because it will just squirt it out and the close the crack. The best method is a pressure test Regards Peter