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Losing power - I think...

4K views 19 replies 7 participants last post by  pitweasel 
#1 ·
Hi all,

Can you help me make sense of what's going on with my 2000 Outback, going off of the following?

A few weeks ago, I traveled home (300) miles. Nearly all the way through, my CEL came on. P0133 - O2 sensor. Cleared it and it went away - but it smelled like something was burning. Generally speaking though, the car was running fine.

End of that visit home: something's dripping under the car. Shop looks at it and finds that the undercarriage has a lot of fluid caked on it, but wasn't quite sure what it was or where it had come from. They tightened the clamps on the ATF lines and checked my levels, which they said looked fine. However, they also pointed to a spot at the bottom of the engine where there was a little seepage, and said it *might* be a head gasket issue. No leakage in the week and 400+ miles since then.

However: since getting back to work and doing a lot more stop & go driving, I've started having power problems. It'll feel like the engine wants to stall out on me, and at one point yesterday my RPMs shot all the way up past 4k just to get to 40MPH. Sometimes the car seems fine, and sometimes the engine will kind of rumble and feel like it's puttering out while I'm stopped or going really slow (backing out, leaving an intersection, etc). I'm worried that I'm going to end up stranded somewhere if this doesn't get solved quickly, but I'd like to try to at least have something to go on before taking it to the mechanic. Any thoughts? Thank you!
 
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#2 ·
how do you feel about this shop? Do they see many Subarus?

I think you should have your fluid levels and fluid color checked again.

is the cel on again?

maybe someone can suggest a soob-experienced mechanic near Lilitz.
 
#3 ·
Forgot to mention...when this latest problem started, my CEL came back on with P0170 - fuel trim malfunction. Could this possibly be a coincidentally timed failure of my fuel pump? Car has over 150k on it, and I don't think I've ever had that replaced.
 
#4 ·
150K is the point where a few things start needing replacement. Spark plug wires can be degraded and start shorting due to leaky Valve Cover gaskets which tend to happen around 140-150K on a car that has seen proper oil changes its whole life. Not a big deal just one of those old car things that need to be done around that mileage. This could be causing enough of a short that your loosing power. Trace the spark plug wires to the heads and see if you have oil in and around the spark plug. This is the standard indication the valve cover gaskets need to be replaced.

Fuel pumps are known for doing 200+K with zero issues. However if you have an H6 there is a rubber seal in the gas pump that many people are starting to report fuel issues caused by this seal failing and preventing the pump from providing the proper fuel pressure to the engine.
 
#5 ·
the issue with DTCs (the codes stored when a CEL is on) is that they rarely point to a part, just to a system that is out of the expected range set in the ECU's firmware.

You may need an O2 sensor or have some issue with a vacuum leak or bad injector, etc.

A GOOD mechanic can trouble shoot various sensors and likely find/replace the bad part.
 
#6 ·
No real changes after some weekend driving, so looks like it's time to find a shop. A close one. At an intersection, I had to nearly floor it before it would finally kick into gear - and it took me to over 3k RPM just to get up to ~30MPH. Oy.

Sadly, I don't know of any "Subaru" people here, and the dealer isn't an option (I work longer hours than them).
 
#7 ·
if the engine is able to respond to the accelerator pedal and rev appropriately, but the car isn't moving appropriately, then I'd be looking for trouble in the trans. Have someone else re-check ATF levels (or learn to DIY). This fluid transfers the force of the engine to the transmission, and if you are low the engine will have to rev much higher to get the same car movement. Shifts are usually delayed and sloppy in this condition too.

A poor idle/stalling condition would be unrelated to the above, though, so if it is a low ATF condition you may have a second issue as well.
 
#8 ·
A poor idle/stalling condition would be unrelated to the above, though, so if it is a low ATF condition you may have a second issue as well.
Yeah, that's what worries me. Sometimes when I'm stopped at a light or pulling into a park space, the engine will be kind of chugging, like it wants to stall. But the sloppy response to the gas was making me think transmission. Is there some sort of scenario in which the two could be related - one problem that's causing the other one? Or could I just have something awesome like a head gasket leak and a failing transmission at the same time?
 
#9 ·
Sounds like a clogged catalytic converter to me.
 
#10 ·
Really? A few years ago, the car was throwing multiple codes - including P0420, which the shop said may or may not be the CC. After replacing the knock sensor (which was also throwing a code), P0420 also went away. Again, this was several years and nearly 70,000 miles ago.

What exactly does the catalytic converter do? That's something I've never been clear on, but I'd heard that it wasn't unheard of for them to cause problems in the '00 Outbacks.
 
#12 ·
My 1997 Nissan Altima was stalling at stoplights and also sputtering on the highway and not maintaining constant rpm. I replaced the air filter (which was a mess), but that did not help. Mine ended up being a $400 mass airflow sensor replacement, but a couple other things may be the culprit. Check the fuel filter. If it runs fine wide open on the interstate, but has issues running 2K rpm speeds it may be the fuel filter. It could also be a vacuum leak somewhere. Check Eric the car guy on youtube. He has a way of checking for vac leaks that seems simple
 
#14 ·
Hmm. After reading some external links on CC failure, this certainly sounds like it could be the culprit. However, the fuel trim malfunction code makes me think that it's something else. Or, knowing my luck, it could be both. Can't call any shops about it tonight, obviously. Tomorrow will be a challenge!
 
#15 ·
The fuel trim code could definitely be related to a clogged converter.
 
#16 ·
Just got off the phone with Orbachs (aka Dr. Subaru) and he said that he'd be shocked if it were a clogged catalytic converter. He suggested it was more likely the front O2 sensor - problematic with that model and would display similar symptoms. Anyone think he could be right? I can't get the car to him for another month, so I'd love to try troubleshooting a potentially/relatively minor issue like that if there's any reason to chase it down.
 
#17 ·
Find out how much the sensor is and how difficult it is to get to. Then decide if you want to try to change it out yourself. They typically aren't too difficult to change; I've changed them out before and the ones I've purchased have been about $45.

I know prices vary considerably and that some manufacturer vehicle makes/models are pretty finicky about the brand of O2 sensor that will work without an issue. I'm new to Subaru so I don't have enough knowledge yet to know if this is an issue on Subaru.
 
#20 ·
Update: resolved! I think...

I managed to get it in to a shop that doesn't advertise at all and yet does extremely steady business exclusively on Subarus. They listened to my descriptions, took it for a test drive, looked at the type of O2 sensor in the front and immediately said "no question - that's where your problem is." The car felt like it would die on the way to the shop, and again during the test drive. In the ~30 miles or so that I've put on it since, it's been fine. I do wish I'd had the resources to try that replacement out myself instead of having someone else do it, but again...time just isn't kind to me right now.
 
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