bendecker Posted January 20, 2015 Share Posted January 20, 2015 (edited) Help, please. My '96 legacy will run fine for a very long time, but on rare occasions (once every month or two), it will lose power going up a long steep hill. I keep giving it gas and it keeps slowing down. Of the last 6 or so times it has done this, it had me pulling off the road as it sputtered to a stall. I did a restart, it sputtered just a bit, then seemed fine. (The other time, it came painfully back to life while still driving.) Background: 1. 1996 Legacy, AT wagon. 2. 260K Miles 3. New MAF, NGK plugs, NGK wires, Autozone fuel filter, Ebay Special knock sensor, junkyard coil and Bosh downstream 02 sensor (all 2 months ago) 4. New OEM fuel pump (1 year ago) 5. Did a vacuum check for a clogged exhaust. No obvious problems found. 6. Checked for vacuum leaks, no obvious problems found. 7. No CEL. My guesses at this point are: 1. Partially clogged CAT? Maybe some pieces that are not in the way at slow speeds, but when the throttle is wide open on a long hill and it's blowing tons of air through the system, they clog the cat. (How would I check for this?) 2. Some type of fuel delivery issue? If fuel can't quite keep up, the system would "refill" when the car is restarted. I have not actually checked the fuel pressure. Again, I have a close to brand new OEM pump and new filter. 3. Fuel pickup problem? Partial clog? The car had a bit less than 1/4 tank this last time, if that makes a difference. Don't know what it had in it the other times. 4. Something wonky with the ecu that resets when the car is restarted? Any opinions? Thanks. Edited January 20, 2015 by bendecker Link to comment Share on other sites More sharing options...
Rooster2 Posted January 20, 2015 Share Posted January 20, 2015 Doubt that it is a clogged cat. I experienced that some time back. When clogged, exhaust becomes so restricted, that engine rpm would not go above about 2800 at any time. Also, when cat is bad, the media inside the cat breaks into pieces that create a rattle noise at idle. It's when those pieces clump together that trouble results. I suspect you have some fuel delivery problem. With a steep hill climb, you give extra throttle, but the system may not be able to respond to keep up with demand. I read that your fuel pump and fuel filter are rather new, but even "newer" parts can still fail. If it were me, I would replace the Autozone fuel filter with a name brand fuel filter. I suspect the Autozone filter is made in China, with who knows what quality. This may, or may not fix the problem, but it would be a good place to start. Link to comment Share on other sites More sharing options...
forester2002s Posted January 20, 2015 Share Posted January 20, 2015 It is interesting that this happens when both of: - Low fuel-tank-level; and - Going uphill. If you could confirm these two juxtapositions, then it would lead you closer to the solution. 1 Link to comment Share on other sites More sharing options...
moosens Posted January 20, 2015 Share Posted January 20, 2015 Or could be the coil pack has a slight crack you can't see. Undr load it shows. Not under load you'd never suspect you have any problem. I've run uphill with low gas and I believe you don't really have a problem with 1/4 tank on any hill. Link to comment Share on other sites More sharing options...
bendecker Posted January 20, 2015 Author Share Posted January 20, 2015 (edited) I doubt that it's the coil pack because the car did it both before and after I put in the junkyard coil pack, but I could be wrong. It just seems to me that the odds of it doing the exact same thing with two different coil packs would be pretty small. Especially when the "newer" pack helped solve a different problem (startup hesitation and lack of power in general). Edited January 20, 2015 by bendecker Link to comment Share on other sites More sharing options...
moosens Posted January 20, 2015 Share Posted January 20, 2015 Ok well i tried .... Let us know what you found instead of letting the thread die off , please. Cheers! 1 Link to comment Share on other sites More sharing options...
moosens Posted January 20, 2015 Share Posted January 20, 2015 No "misfire cylinder four" ? Link to comment Share on other sites More sharing options...
bendecker Posted January 21, 2015 Author Share Posted January 21, 2015 No "misfire cylinder four" ? Not now, but I used to get that code before doing all the changes listed in the first post. What should I know about that one...? Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted January 21, 2015 Share Posted January 21, 2015 has it ever done it with the engine still cold? you said no CEL but, have you scanned for pending codes? TPS might be possible culprit. some folks have had crank position sensors be intermittent when they get hot.(dunno why you wouldn't get a code for that though) just some wild guesses. Link to comment Share on other sites More sharing options...
libertyherb123 Posted January 21, 2015 Share Posted January 21, 2015 Seems to be a very common problem. I had the same problem with my 91 Legacy. From the studies and fault finding I did it is caused by carbon build up and sticky valves which cause a loss of compression under load. I would recommend using Marvel Mystery Oil. Put some sea foam through the intake. Short of doing a valve job you need to try to free the sticky valves and remove the carbon build up. The issue will only occur on a long hill under load. If you pull over it will shudder and shake on 3 cylinders and then it will clear itself. Some people have also had some luck replacing the ignition relay. 1 Link to comment Share on other sites More sharing options...
moosens Posted January 21, 2015 Share Posted January 21, 2015 Right along those lines above - I was told by a legendary 30+ year Subaru tech that those earlier EJ'a and up to around 96-7 , which our Legacy wagon was with the Same problem , that cylinder 4's valves or maybe just exhaust valve are/is sticky often due to the cold and of course some carbon build up. The way he explained it the exhaust port allows that particular valve to get more "weather" thru the exhaust pipe. His words , just repeating. And upon load will present itself. Our 96 2.2 had the same problem as first post. We would get on a highway entrance ramp near our home and same thing all the time. Pull over and as stated above it'll correct itself. Reason I had mentioned the coil pack was I just solved a similar issue on our 95 Impreza 1.8 but that also involved backfiring. I guess if you feel it's the cylinder 4 thing try as mentioned above. We had a couple accidents with that car so we let it go before ever truely solving that issue. As mentioned - valve job - or just try the cheapy methods first. MMO might help. 1 Link to comment Share on other sites More sharing options...
bendecker Posted January 21, 2015 Author Share Posted January 21, 2015 (edited) From One Lucky Texan: "has it ever done it with the engine still cold? you said no CEL but, have you scanned for pending codes? TPS might be possible culprit. some folks have had crank position sensors be intermittent when they get hot.(dunno why you wouldn't get a code for that though)" A: The engine has always been at full temp when this has happened. We live in So Cal, so engines warm up quickly. Edited January 21, 2015 by bendecker Link to comment Share on other sites More sharing options...
bendecker Posted January 21, 2015 Author Share Posted January 21, 2015 (edited) From all your posts, sounds like valves is a good place to start. I have seafoam and Lucas for the gas/intake (side note: Lucas does wonders for my '93 Impreza's power and mileage). I'm assuming you mean MMO in the crankcase, though. What exactly is involved in a valve job? I've only done that once, years ago, on a Chevy Luv (piece of junk) and it mean't pulling the head with engine in place. I'm assuming I'd have to pull the engine on the legacy (new territory for me) before pulling the heads. I'll do some research. Any other way to check for sure about the valve? Edited January 21, 2015 by bendecker Link to comment Share on other sites More sharing options...
99lego Posted January 21, 2015 Share Posted January 21, 2015 From all your posts, sounds like valves is a good place to start. I have seafoam and Lucas for the gas/intake (side note: Lucas does wonders for my '93 Impreza's power and mileage). I'm assuming you mean MMO in the crankcase, though. What exactly is involved in a valve job? I've only done that once, years ago, on a Chevy Luv (piece of junk) and it mean't pulling the head with engine in place. I'm assuming I'd have to pull the engine on the legacy (new territory for me) before pulling the heads. I'll do some research. Any other way to check for sure about the valve? Best of luck to you in tracking down and solving this issue. It's plagued my Phase II 2.2 for quite some time and I've thrown the world at it trying to figure it out. My solution thus far has been dropping her into 4'th and pushing the skinny pedal to the floor until she evens out. Link to comment Share on other sites More sharing options...
libertyherb123 Posted January 21, 2015 Share Posted January 21, 2015 Sorry, yes MMO through the crank case. Sea foam through the intake. You can also try some BG44K in the fuel system. Unfortunately with the high mileage it can be very hard to clear. I know this sounds silly but you can avoid the problem by just taking your time up the hill. Don't put it under so much load and just go slow. Everytime you do this to replicate the issue it has the potential to make the valves worse. As far as a valve job on my ej22 it means pulling the engine (it can be done in situ but for someone more skilled than me) I am not sure about the 96 but I imagine it will be the same. Link to comment Share on other sites More sharing options...
libertyherb123 Posted January 22, 2015 Share Posted January 22, 2015 Here is the link to the page I started but there are countless numbers of this issue occurring and many many pages to read of people with the same problem. http://www.ultimatesubaru.org/forum/topic/143243-1991-subaru-liberty-loses-power-under-load/ 1 Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 22, 2015 Share Posted January 22, 2015 Is it the 2.2 engine? A stuck open valve could be caused by blocked or partially blocked bleed holes for the hydraulic lifters. Marvels mystery oil can help with that. The lifter pumps up too much, and the valve hangs open until the oil bleeds out of the lifter. Takes 20-30 seconds for the oil to slowly bleed back out, the valve can then close and compression returns. 2 Link to comment Share on other sites More sharing options...
bendecker Posted January 22, 2015 Author Share Posted January 22, 2015 (edited) Here is the link to the page I started but there are countless numbers of this issue occurring and many many pages to read of people with the same problem. http://www.ultimatesubaru.org/forum/topic/143243-1991-subaru-liberty-loses-power-under-load/ The last comment about the relay is interesting and libertyherb123 mentioned it earlier: "i have just fixed my mums car with this exact problem but i probably tested and changed out more parts than you have... what it was in the end up above the fuse panel on the drivers side is a brown 6 pin relay that open circuits when faulty and cuts injector pulse under load it would do it uphill in exactly the same spot every time... how weird.... look for a brown relay it is right up near the windscreen pt no is 25232aa000 you can buy it on ebay hope this helps every one as a lot of people have the same problem when you google it." Seems kind of counter-intuitive. I put more credence into the valve issue, but anyone have any experience with this? BTW, wrong part number for a '96. Edited January 22, 2015 by bendecker Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 22, 2015 Share Posted January 22, 2015 6 pin relay would be the main relay which would cut power to everything engine computer/ fuel injection related. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted January 22, 2015 Share Posted January 22, 2015 years ago, my middle daughter owned a 90 maxima that would occasionally stall-out, most often when turning thru an intersection. it was the 'motor control relay' . $20 fix. so, I believe it 'could' be something like that. (suggested to me on the nissan Usenet group by a Nissan Tech in Florida - gotta luv the internet!) Link to comment Share on other sites More sharing options...
bendecker Posted January 22, 2015 Author Share Posted January 22, 2015 (edited) Experiment #1 starts: 1) Swapping a quart of oil in the crankcase today with a quart of Marvel Mystery Oil. 2) Will drive only on flatter roads (I have other cars to drive on the hills that cause problems) and will take it easy on the car. 3) After a 200-300 miles, will try going up a steep, long hill and see what happens. Any other advice...? Hoping for a miracle... Edited January 22, 2015 by bendecker Link to comment Share on other sites More sharing options...
mzop Posted January 31, 2015 Share Posted January 31, 2015 I have similar problem but its constant, had 2 mechanics tell me my cats are bad. I do hear a rattling from exhaust pipes, not sure if its my heat sheild or not. I can get my rpms up pretty high but car won't accelerate while rpms are rising. Mine doesn't stall and has no cel. Link to comment Share on other sites More sharing options...
bendecker Posted February 19, 2015 Author Share Posted February 19, 2015 If anyone is still following this thread, I've driven for about 300 miles (car doesn't get used much) on pretty much flat ground with a quart of MMO in the crankcase. No issues to report. Thinking I might try to pull a moderate hill today... Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 19, 2015 Share Posted February 19, 2015 If you've driven 300 miles, change the oil and add some new MMO, then go try the hill. 1 Link to comment Share on other sites More sharing options...
bendecker Posted March 7, 2015 Author Share Posted March 7, 2015 Update: I changed the oil and put in another quart of MMO. Drove it about 100 miles before pulling a hill. I've now pulled a pretty long hill 3 times taking it really easy (have not pulled the hill from hell yet that killed it big-time before). Unfortunately, that means I've changed two things -- the oil and my driving habits. But, I don't want to gun it up the hill, 'cause So Cal is NOT the place you want to have a car die on the freeway. No issues to report so far. I do have a pretty low comfort level with it still, so every time I pull a hill it's a wee bit of a white-knuckled ride. That should pass if I keep having successes. So far, so good... 1 Link to comment Share on other sites More sharing options...
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