SubieBlue Posted November 2, 2011 Share Posted November 2, 2011 Here's the story: I bought a 1999 Legacy Brighton 5spd 2.2 in September of 2010. I made the purchase (after years of making fun of Subarus) for all that I had come to learn about them: reliability, safety, and anywhere AWD. I love the car and have put 15k miles on it. There's only one problem - it goes through times where it stumbles/hesitates when shifting and when I release/depress the accelerator at regular driving speeds. This stumbling is many times pronounced enough to move your head in a whip-lash motion - you most always feel it in the seat of the pants. I say that this is a "phantom" problem because I've tried the following remedies which SEEM to work but in several hundred miles (or less) the problem is back: 1. Replaced valve cover gaskets (they were leaking into the plug wells...thought this was messing with the firing of the plugs. 2. Replaced the coil/plugs/wires (code scanner said there was a misfire on one of the cylinders.) This seemed to fix it...for a little while. 3. Replaced fuel/air filters (just in case). 4. Replaced fuel filler neck. Was getting PO440 and PO453 (Evap) codes. The filler neck was quite rusty and began to actually leak. Car ran good but soon was stumbling again. 5. Mechanic checked for vacuum leaks. None were found. 6. Unplugged the knock sensor to see if the stumble went away. Thought that it was possibly too sensitive and was mis-communicating with the ECU. Stumble was muted but very much present. 7. Engine was surging and began to run very roughly plus we had a TPS code. Replaced the TPS and it ran great for about 400 miles. Thought that the problem had been found for sure. Tonight it randomly began stumbling again. 8. There's one ongoing issue: The PO453 and PO440 codes are still there. (Check engine light comes on and off seemingly at random.) On top of, and possibly related to this issue is the fact that it will sometimes not allow me to put fuel in the tank. Pressure builds up and it will "spit" the fuel back out. The pressure is great enough that I really have to leave the cap off for a while and then go get gas. Any ideas? I love Subaru's but this phantom problem is driving me crazy! Quote Link to comment Share on other sites More sharing options...
Legacy777 Posted November 2, 2011 Share Posted November 2, 2011 Welcome to the USMB. Regarding your fueling symptoms and codes, I would suggest testing/replacing the canister purge solenoid. It is located under the passenger side intake manifold and is supposed to open at cruise to allow the evap emissions to be drawn into the engine. The other piece to the evaporative emissions system is the charcoal canister. I'm not sure whether on your model if the canister is in the engine bay behind the passenger headlight or under the passenger side of the car in the rear near the fuel tank. I would suggest checking to make sure there is no obstruction in the evap emissions line from the tank to the charcoal canister, the purge solenoid, and then into the engine. I'd start with trying to eliminate that issue before doing any further diagnostic work on the stumbling/hesitation. Quote Link to comment Share on other sites More sharing options...
wildwagonz Posted November 11, 2011 Share Posted November 11, 2011 Not sure of this is an answer to your problem, but I had an 01 Legacy that was stumbling and surging I replaced lots of stuff and it still did it, ended up being the screen on the fuel pump in the tank was full of rust....removed the screen and it ran perfectly Quote Link to comment Share on other sites More sharing options...
the3rsss Posted November 11, 2011 Share Posted November 11, 2011 I also had a p0440 code on my 99 obw. I replaced the fillerneck and rollover valve and the light went out but she wouldn't take gas. I reversed the hoses to the rollover valve and it took gas again. Did this fueling problem start after the fillerneck was replaced? As far as the stumbling., I would get two cans of seafood. Put one in a full tank of gas and the other into your intake. Preferably thru the tb. Quote Link to comment Share on other sites More sharing options...
the3rsss Posted November 11, 2011 Share Posted November 11, 2011 SEAFOAM SEAFOAM! Damn autocorrect! Quote Link to comment Share on other sites More sharing options...
Olnick Posted November 11, 2011 Share Posted November 11, 2011 I would get two cans of seafood. Put one in a full tank of gas and the other into your intake. Preferably thru the tb. That's classic--I love it! Thanks. Quote Link to comment Share on other sites More sharing options...
rujoking Posted November 15, 2011 Share Posted November 15, 2011 (edited) As far as the stumbling., I would get two cans of seafood. Put one in a full tank of gas and the other into your intake. Preferably thru the tb. You'd be better off taking it to a professional tuna. EDIT: Seriously though, Seafoam it like it's hot. :snoopdog: Edited November 15, 2011 by rujoking Quote Link to comment Share on other sites More sharing options...
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