starting/stalling issues 2008 legacy

[NoviceSubyOwner]

Hey! Just want to start out by thanking this community for all the help over the years diagnosing and fixing my Subaru's. Without you guys I would have struggled to find my way learning to work on cars.

The issue I'm having this time is with my wife's 2008 Legacy. She's having starting and stalling issues. The other day she had a hard time turning it over and had to pump the gas to get her started. It's not throwing any codes. The next day it stalled out on her twice. Once going around a turn and once in the driveway. It was idling really low when she slowed or came to a stop.

My initial thought was fuel pump as there have been fuel issues in the past. A couple of years ago she had a strong gas smell and I removed the fuel pump when the gas gauge read about half full. The tank was actually full It poured gas out when I did. Since then if she keeps the gauge around half full it doesn't smell of gas inside the car.

I replaced her spark plugs too a while back when the car threw a code for cylinder misfire. It fixed the problem but I noticed there was some oil on the old spark plugs when I removed them. Not sure if that is related to what's going on now but thought I should mention it.

Any help would be much appreciated as always.

Update 1: She started right up no problem. However, I did get a CEL this time along with flashing cruise light and an error on the trip odometer reading "Er AA"

The codes are as follows:

p0304 cylinder 4 misfire

p0302 cylinder 2 misfire

p0700 transmission control system (MIL request)

p0715 turbine/input shaft speed sensor circuit

then it repeats p0302, p0304 and p0700 for a total of 7 codes.

 

Edited April 16, 2023 by NoviceSubyOwner

[KZJonny]

Standard Legacy or GT? Doesn’t change the meaning of the code, but may change what you need to do in subtle ways…

[NoviceSubyOwner]

Standard

[KZJonny]

Okay. I can’t say much about the tranmission issues. But that does mean you’ve got a 4EAT, not a 5EAT. Might help someone else diagnose you a little.

Since you don’t have coil on plugs, you  can’t try swapping coils to see if the problem follows the coil packs. Sometimes coils get old and begin to fail with heat, so it’s possible to idle the car and use a hair dryer or heat gun to heat the coil and see if the misfire occurs. This would be time to get a new coil, and most likely plug wires as well. You also might be able to see failing wires if you have somewhere with no lights around and look under the hood with the car running. Misting around the wires and coil with a water bottle can also show up bad parts, as if they are failing, the may arc through the water mist… I don’t remember how the coil on the Na engines works, but I assume it’s wasted spark, and cylinders 2 and 4 both get an ignition at the same time, so the two cylinders on the same side suggests a bad coil. (I should know this, I have a 2.5i as well, but haven’t had ignition problems… yet.)

The oil on the plugs is most likely failing(ed) plug tube gaskets. Time for a new cam cover gasket set. Common for older cars. Not the worst job on sohc engines. You’ll want a ratcheting wrench set ideally, there still isn’t much room there between the heads and the inner fender.

Fuel smell suggests a failing filler neck to me, which is another common problem, since there is a small plastic sheild as part of the wheel well liner that tends to hold dirt and gravel against the filler neck, causing corrosion. I’d have a quick look there. At 15 years old, the tank could also be rusting at the seams, which may also cause a strong smell above ~1/2 tanks. (This is actual tank volume, not based on what sounds like a bad fuel sending unit…)

Hope some of that helps.

Edited April 17, 2023 by KZJonny

[NoviceSubyOwner]

Wow. Thank you so much. I appreciate the time you put into that response and it was incredibly informative!

I'll be sure to update as I go and let you know.

[KZJonny]

NP. Do report back if you get any results. There are definitely more than just those things that could be causing your problems, but they were the first and most obvious that came to mind.

(Editing out useless info....)

If the car is in good shape, and you don't mind spending a little money on it, I'd check out the trans code first... check the colour of the fluid, would be cherry red if new, and various shades to deep brown if it's really cooked. Top up if low and see how it behaves, I know from my OBW that when I was leaking a little ATF from a trans cooler line, it didn't need to be down by very much at all to cause some serious problems in how the car behaved and shifted, stalling would not surprise me as a symptom either. That would be the deciding factor for me. Used 4EATs are cheap enough, and relatively bulletproof. But it would be the most expensive fix by a lot. Coils and wires, or a fuel sending unit are easy to do and (relatively) cheap. Trans is meaningfully less easy to do in a driveway, and only cheap(ish) if you have a way to get one from a scrapyard.

If the code reader is correct tho, it may be the input shaft sensor.... and that isn't too expensive, but probably best to double check how ot diagnose if it is actually faulty before just throwing money at a problem.

https://parts.subaru.com/p/Subaru_2008_Legacy/Vehicle-Speed-Sensor/49242496/31937AA122.html

Edited April 17, 2023 by KZJonny

[KZJonny]

https://www.subaruoutback.org/threads/weird-er-aa-code-on-odometer.148001/

Also an interesting post. Seems ErAA is commonly associated with CAN problems... any chance you've got any kind of auxiliary devices that could be messing with it?

Just more ideas to kick around.

[NoviceSubyOwner]

She does have a car starter that I had installed for her a few years ago... Tranny fluid looks good.

[KZJonny]

Yeah, that colour looks okay. Level was okay as well?

So maybe ignore the Er AA or now, since it seems to be a bit of a hard thing to track down, and what evidence is available suggests radio or other interference... If the remote starter didn't cause that problem on install, why would it now?

If the coils and wires don't show any signs of damage, or at least pass the stress tests, then I dunno?

I should have started with this as well: Nothing you are doing with any electrical system means anything unless your battery is fully charges and you've got good ground cables that aren't super corroded. Sounds like you're on top of basic maintenance for the car, so that wouldn't be such a big problem, but it's worth a look.

Bad grounds cause all sorts of headache that appears as other things, and a tired battery will do the same. Could be worth having it load tested to make sure it's good. (Unless very new, and alternator charging ability is known to be good.)

[NoviceSubyOwner]

Level is ok. I just cleared the codes and took her for a drive and didn't have any issues.

I'll have to check the battery but it's not old. Maybe a couple years? I'll check the grounds too.

I have a great local mechanic that I only go to for inspections but he does just about everything and he let's me know when the car needs something so I can fix it myself. Gonna see if he'll take a look and I'll go from there.

Thank you for all your help! I'll keep updating for others with similar issues.