Subaru Forester 06 - fuel delivery problems



My 06 Subaru (stick) has works just fine until someone else drives it. (Won’t say who!) After that guy, whose foot is somewhat leaden, drives it, I with the light foot find the car stalls, is slow to catch, and stalls. 4 times, I have taken it to the dealer mechanic and he fixed it just fine until…

So, the first time, mechanic said it was a fluke. The 2nd time, he said it was a design flaw. The 3rd time, he said the car will re-set itself to save fuel for a heavier footed driver. The 4th time same. It still seems like a design flaw in that it outsmarts lead-foot and then behaves like a stubborn donkey when light-foot drives. If it is a design feature, is there a way to get rid of the feature (much like people took off the early smog devices)? The two other options are not ok by me. Those are: get rid of the car or get rid of you-know-who. Help!


ps - I’ve been driving stick since 1964 and this feels like the first week I drove or gas in the fuel (nope- gas this time is fine)


Too many things could cause it. Broken engine mount and some features that used t go on other cars was a flaky clutch adjuster which you may not have. A clutch cable support clamp could be broken. There are more and someone else will probably post more possibilities soon.


Thank for your thoughts. I hope (and doubt) my Subaru’s stalling, lugging’balking problem is as bad as what you suggest. When the dealer mechanic fixes it, it stays fixed until the guy whose name won’t be mentioned drives it. It’s after he drives it, that the problem presents again. I yearn for a more durable fix. I’m still looking for ideas to get the dealer to replace the parts that try to outsmart a lead-footed driver. The car goes in soon.



Can’t say as I’m impressed with the things you’ve been told.
You state they’ve fixed the problem several times but you have not stated exactly what “fix” was done. Surely some valid mechanical details would have been explained to you other than the BS you’ve been told.

Drop by an AutoZone, Advance Auto, Checkers, etc. and have them scan the car first off. They will do this free. Post any results back here.
There are a number of things that could cause this but pulling codes should probably be the first step.

Additional info. Any Check Engine Light coming on? Rough idle? Any shudder taking off from a dead stop?


Thanks - I’ve not been impressed w/ the dealer’s vague info either. I’ll call them and press for it. Here in hinterlands, no AutoZone, etc. but I’ll ask another mechanic here. By pulling codes, do you mean the computer print-out of what’s what, or do you mean are any parts / schematics flaky? No, the engine light doesn’t come on (except after it stalls – normal); slightly rough idle; and, yes, shudder sometimes from dead stop, then sometimes stall. It wants more gas, I give it, then, of course it revs. If I don’t give it gas, it wants to stall (from dead stop, to higher gear, in reverse too). The engine has a time-lag in catching the fuel I give it. And, it tends to lug (giving more fuel / increasing RPMS seems to help). But it “needs” higher RPMs than it did before. Before = for a long while after mechanics fix it, until Someone Else drives it.
—StickShift Nana


A scan tool should pull up codes and display them on the readout. This process only takes a few minutes.
There are no chain store type parts houses where you live? Checkers, Schucks, Kragen, maybe even O’Reilly?
There may be codes present even if the CEL is not on.

I’m leaning towards all of these problems being coincidental and your friend not being at fault.
A rough idle and stalling could mean a vacuum leak. The leak could be anywhere in the vacuum lines or anything controlled by vacuum. Even the position the cabin mode control is in could have an affect on this (A/C, heat, DEF positions, etc.)
This could be inspected with the use of a vacuum gauge; something that apparently the vast majority of mechanics don’t or won’t use. It’s very simple to do.

Other possible causes of something like this could be an EGR system fault or an Idle Air Control Valve fault. Both of these are essentially vacuum leaks; they’re just ECM (computer) controlled ones.
It’s possible an EGR code could exist in the ECM memory; the IAC one may not.
JMHO anyway and hope it helps.


Is the maintenance up to date?
When was the last time the fuel filter was changed and isopropyl dry gas added? If you have not been useing dry gas, there may be water in the fuel.
Use isopropyl dry gas once a month.
Replace the fuel filter every 15,000-Miles.
Cover these items first before doing anything.
Ok4450 had good advice too.
A heavy foot will not hurt it, this car will take all you can give it.


Be sure to use the octane gasoline the car maker says to use. If you don’t, this driveability problem you have could be caused by that. Ask the car maker (Subaru), if you doubt.
If you are paying for these “temporary” repairs, take the car to an independent shop. They may perform a “permanent” repair.
A good mechanic could use a scan tool, to watch sensors and actuators in dynamic setting (throttle movement, etc.) and, possibly, uncover some irregular responses of sensor)s) or actuator(s). Hope you can find good mechanic.


After you drive it a while, does the Subaru become more driveable? The computer will adapt to different driving styles but usually it is just filling in the map you don’t use, i.e. Wide Open Throttle low RPM.

Let us know.


So - thanks, folks! The car is still under warrantee, so dealer does work and I think they’re ok. I can’t wait to take it to Ray - our regular and fantastic mechanic. Re: your ideas:
ok4450: nope, no outfits here like you say - perhaps NAPA which is here. I am not keen on buying a widget for reading codes, with all due respect. Yes - there is a difference in engine/RPMs when the heater or AC are on, and it’s a more significant change than in any other rig I’ve driven. I’ll ask Ray to check it.
Lee…: you bet, I’m on maintenance (two dead cars in the 60s taught me that!).Dry gass? hmmm. I’ll look into it. What do others think.
Hellokit: Octane, etc. Oregon just lowered our Octane and many are irked, getting low MPG and degraded performance, but the gas is what Subaru says, and it’s as dry as it comes. See above re: good mechanic and our guy Ray.
Research: no - it doesn’t change in both directions: when heavy-foot drives, the car is designed to re-set (supposedly to save fuel); it won’t re-set for a lightfoot, oh darn.

And, the update: just got a call from the dealer - the 06 Subaru had a mfg.'s change on the throttle sensor. They said they adjusted it according to the new numbers. (Yes, they did hook it up for a computer print-out; sorry, no vacuum test, that and other appropriate mechanic’s processes will be for Ray, when we graduate from warranty. The car has about 9,000 on it (not quite time for air filter change and I don’t live in a dusty place), oil has been changed every 3 mos or 3000 mi., and etc.

The dealer’s mechanics re-set the throttle. They agreed that if they car is not ok when I get it, they’ll re-do it. If so, before I let them get their hands on it again, I’ll go see Ray. The dealer’s worked on two of our cars over the years and their work seems fine. And, I trust them more because they pay attention to my reports and concerns and are not powder-puffing me.

So, we shall see. And I hope the report I post after I’ve driven it again, is the last.

Again, it’s been great and I am appreciative.


So- Here’s the current final installment on my stalling/lurching/lugging problem w/ Subaru
Researcher picked up on what was wrong: car’s computer adjusting to driving styles. It does, but it only changes to more heavy-footed drivers, and will not re-set bac to a lightfoot. I was under pressure to gather info before the car went into the shop. So thanks to each of you.

It’s been a week since I picked it up from the Subaru dealer mechanic. They rec’d a factory directive to change the voltage sensitivity on the fuel delivery system to a wider range, therefore accommodating a light foot, regardless of the car’s auto re-set. The car has given me no problems since. I wanted to let a week’s worth of driving go by before this report. I am satisfied for now. The test will be to see how it is after a heavy-footed driver uses it!


Thanks for the update SSN. Hope it gives you no more trouble. It sounds like lead foot should get a WRX STi and leave your car alone.