Another weird problem

[TBR]

Okay, so my mother says that after getting a full tank of gas her 2004 5-spd Subaru Outback feels like it's misfiring for about a mile or so. This is a consistent problem, always occurring after a fill up and disappearing very quickly. Since it is out of warranty already it would be good to have a general idea of what it might be before we take it in.

Also, there is the issue of where to take it. As most of you probably recall, I live out in the boonies. The nearest Subaru dealer is over an hour away. So, would it be safe to take it to a local place specializing in imports or should we go ahead and make the trip to the dealer? My thought is if the problem is most likely with the engine we should go to the dealer since the H4 is a pretty unique configuration, but if it is a gas pump/gas tank problem (as I suspect) the local place should be fine. Thoughts?

[JWC]

Okay, so my mother says that after getting a full tank of gas her 2004 5-spd Subaru Outback feels like it's misfiring for about a mile or so. This is a consistent problem, always occurring after a fill up and disappearing very quickly. Since it is out of warranty already it would be good to have a general idea of what it might be before we take it in.

Also, there is the issue of where to take it. As most of you probably recall, I live out in the boonies. The nearest Subaru dealer is over an hour away. So, would it be safe to take it to a local place specializing in imports or should we go ahead and make the trip to the dealer? My thought is if the problem is most likely with the engine we should go to the dealer since the H4 is a pretty unique configuration, but if it is a gas pump/gas tank problem (as I suspect) the local place should be fine. Thoughts?

If the service advisor at the dealership is decent, he/she will answer some questions over the phone, especially if it is something he/she knows you have to return to the dealer for.  The problem with diagnosing something like that is that if the problem doesn't last long enough or is setting a code on the OBDII, an independent will just recommend something like a fuel filter, air filter, or throttle body cleaning.

Many time there are computer updates through the manufacturer that remedy such problem.  My wife's Taurus developed a shuffle as it changed gears, as if it wasn't sure it wanted to up shift or not. Not a big problem, just something that I knew wasn't quite right. I checked TSB's at work and sure enough, the newest calibration for her Taurus listed "transmission shift shuffle". Cured it with a software upload.

[TBR]

So just have my mother call the Subaru dealer and ask for a service advisor?

[JWC]

Yeah, can't hurt. Explain the distance she has to travel and the fact the problem is only momentary.  I field phone calls like this all day. Made to the Volvo dealer (closest is 35 minutes away) about an intermittent problem I'm having.

You really have to ask only two questions:

Has he/she ever heard of any other cars having this problem?
Are there any technical service bulletins related to something similar that might help?

[ifcar]

Does she always get gas at the same place?

[TBR]

Nope.

[S204STi]

Does the MIL illuminate?  And does your mother top off the tank after the filler clicks off?  That is a big no-no, btw.

[TBR]

What is the MIL?

She never fills it after the click.

[ifcar]

What is the MIL?

She never fills it after the click.

MIL is the malfuction indicator light, or something similar. AKA "Check Engine" light.

[TBR]

Okay, in that case: no.

She hasn't been able to get ahold of a service advisor, at two different dealerships.

[Eye of the Tiger]

Since the fuel pump and gauge sending units are the only thing in the tank that could be affected by the fuel level, I would check those.
Maybe the full tank is creating an intermittent short in the wiring, either by splashing fuel or somehow by the position of the fuel gauge sending unit.

You might try hooking up a fuel pressure gauge. Take a look at the pressure when the engine is running normally, and then after you fill up next.

Then you can at least narrow it down to an injector, ignition or ECU problem, which seem to be less likely considering they have little to do with the fuel level.