Car sucks with up to date map...

Hi guys, I've been noticing in the ~800 miles since I bought this car that it has an often times bad studder between 2-3k rpm in 2nd and 3rd, and usually happens when im light->medium on the throttle.

 

Took it to a dealership, they took it for a few test drives and I watched them beat the piss out of my baby (harder than I had ever driven it), made me wait from 10am->5pm with no rental just to say "No, we couldn't replicate it, we can't reflash your ecu because you have no codes, and your clutch fluid is fine."

 

I was like uh, I'm not sure it has to throw a code to be flashable, so he brought his buddy out who was like "Well, we have the reflashing tool here and you have the most up to date version."

 

So..wtf? I'm not understanding this, and I don't want to call them liars unless you guys can tell me I've been duped here, because they're the only subaru people I know of.

 

hmm..

If you do a search, you will find this is a common problem.

 

I believe the studder fix ROM is either 521N or 522N. If you know of a Suby person with a tactrix cable, you can download your ROM and see what version it is. If your car has never been flashed by the dealer, it probably has 500N or 510N.

 

You can bring it to another dealer. Studder is a fairly infamous issue. They are aware of it. They just don't want to fix it because I've heard the ROM isn't a permanent fix. Driving it hard is a good way to not get studder.

My 2-3K light->medium throttle stutter was eliminated when my throttle body was replaced (under warranty) because it was sticking.

Even if you do have the most current version, you can still be experiencing stutter. I had mine reflashed and it didn't really do much. I've also used the AP and different map revisions with the AP have yielded varying degrees of stutter.

 

If you really want to get rid of it, get your car pro-tuned ... otherwise it's something you have to learn to live with on the LGT.

Despite popular belief, I don't think the studder is ECU related. I am not denying it can be (not always aparently) fixed via different map/pro tune, but it must be something else.

 

My car is stock, has original factory map (510N) and it's studder free and ultra smooth. And my car is not alone, there are many without the studder problem.

 

I am really suprised SOA cannot (doesn't want to?) find the right fix....

I had a '99 OBS 5 speed for 2 years. It had the same exacty studder my '07 2.5LGT 5MT has at the same RPMs. Its the boxer studder, ya gotta get used to it, its not really hurting anything, you just gotta power through it, and learn to upshift later, even if its going to hurt your MPG a tad.

I had a '99 OBS 5 speed for 2 years. It had the same exacty studder my '07 2.5LGT 5MT has at the same RPMs. Its the boxer studder, ya gotta get used to it, its not really hurting anything, you just gotta power through it, and learn to upshift later, even if its going to hurt your MPG a tad.

 

Ahem. Not all LGTs have studder. Maybe it's indeed clutch/flyweight wheel related as someone suggested?

Ahem. Not all LGTs have studder. Maybe it's indeed clutch/flyweight wheel related as someone suggested?

 

Well yours isnt LIMITED, maybe thats what separates us, only a limited number of LGTs have the studder? I feel special.

I still think its the dual mass flywheel that is doing it, but that's just me. The only time I can really notice a studder is in 2nd gear between 2k-3k rpm.

I had a '99 OBS 5 speed for 2 years. It had the same exacty studder my '07 2.5LGT 5MT has at the same RPMs. Its the boxer studder, ya gotta get used to it, its not really hurting anything, you just gotta power through it, and learn to upshift later, even if its going to hurt your MPG a tad.

It's not a "boxer stutter" as you suggest. A very good number of us on this forum came from previous Subaru vehicles, myself included. I used to work at a dealer and have driven every model and every drivetrain option of Subaru, Tribeca aside. I, and most other members, have never experienced this in any other vehicle aside from the LGT. I don't understand it, but it's a Legacy issue.

 

But the Throttle Body thing was interesting, whoever mentioned that.

My 2-3K light->medium throttle stutter was eliminated when my throttle body was replaced (under warranty) because it was sticking.

 

Indeed, we might have teh winner for the mistery...

I have always wondered if maybe the studder was a drive-by-wire issue. Who knows how good the servo is that actually opens the throttle plate? When you log throttle position, is it actual position, or is it commanded position?

I would bet that a fluctuating throttle plate would lead to a studder. Kinda like venting off metered air with an atmospheric BOV, poor little ECU gets all confused.

I wonder if there is a dead spot in the voltage of the throttle plate servo. I know that some linear motors will have a dead spot, or will develop one over time. I wouldn't be surprised at all if the throttle plate servo had trouble holding position in a certain voltage range.

Damn, if that's true, that means:

 

1. SOA hires morons, or

2. SOA is stingy and decided that it's cheaper to reflash than replace TB.

 

Btw, I wonder if anyone of our resident ECU hackers/tuners ever did compare 510N map to 521N/522N (the studder fix one) map... if the difference is in the throttle programming, this could confirm this speculation...

Damn, if that's true, that means:

 

1. SOA hires morons, or

2. SOA is stingy and decided that it's cheaper to reflash than replace TB.

3. All of the above.

You know, 1+2=3

Fixed:)

Is this a problem only with the manual trans cars? My stock 05 LGT 5EAT has no such problem.

the '05's have a studder?

Is this a problem only with the manual trans cars? My stock 05 LGT 5EAT has no such problem.

Jury is still out on the 5EAT, most will say "NO"

Despite popular belief, I don't think the studder is ECU related. I am not denying it can be (not always aparently) fixed via different map/pro tune, but it must be something else.

 

My car is stock, has original factory map (510N) and it's studder free and ultra smooth. And my car is not alone, there are many without the studder problem.

 

I am really suprised SOA cannot (doesn't want to?) find the right fix....

 

never had the problem either stock or stage 2 car is super smooth.

My '07 5MT LGT Limited has Si Drive. I have been driving to work in "Intelligent" (180 Miles Round Trip) because I figure I could get better gas mileage. Today I switched to "Sport" to observe my MPG and the studder. I notice with more power at the lower rpm's the studder is either non-existent or lessened. I believe it is a harmonic issue that the has to do with two things, frequency of pistons firing at the low rpm's and fuel being burned, or combustion energy. The Sport map obviously increases HP at lower rpm's over the Intelligent map. I think what I meant in previous posts, that "powering through" the studder to end it is what Sport mode gives at the low end. Try shifting from 1st to 2nd to 5th around 25-30 mph, youll clearly get the same studder, if not a stall. If your LGT is smooth and you do not studder then i truley think its a power issue. If its a combination of power and frequency, is this a timing issue?

I have always wondered if maybe the studder was a drive-by-wire issue. Who knows how good the servo is that actually opens the throttle plate? When you log throttle position, is it actual position, or is it commanded position?

I would bet that a fluctuating throttle plate would lead to a studder. Kinda like venting off metered air with an atmospheric BOV, poor little ECU gets all confused.

I wonder if there is a dead spot in the voltage of the throttle plate servo. I know that some linear motors will have a dead spot, or will develop one over time. I wouldn't be surprised at all if the throttle plate servo had trouble holding position in a certain voltage range.

The dealer had to do extensive data logging while driving to fix mine. If my car wasn't occasionally stalling out while coasting to a stop in cold weather (20F or so) last winter, it would not have gotten the attention from SOA or SNE as we were starting to get into lemon law territory.

 

What they ultimately found in the logs was that the commanded throttle angle and observed angle was different. For example, while coasting to a stop in gear (5MT), the throttle plate is closed and there is no fuel delivery as the wheels are driving the engine. Upon disengaging the clutch, they could see the RPMs drop, the ECU add fuel, but they were not always seeing the throttle plate opening soon enough to prevent a stall. I don't believe they could log commanded throttle position but were inferring it from the fuel delivery. I believe they could log the actual throttle position.

 

It is my belief a similar thing was happening during my 2-3K stutter. For me, it was most likely to occur if I coasted at say 2300rpm and then applied light/medium throttle. In this case, the throttle plate would once again be closed. Give a little gas, the ECU adds fuel and commands the throttle plate to open a little, but it doesn't. I suspect that was my stutter. You had fuel being added without throttle for a second or two, probably causing it to run very rich briefly, and the result was stutter or at worst some bucking. When the throttle opened, it likely overshot and opened too far, causing some instability until it reached steady state. It always felt to me like I was rapidly jabbing the throttle repeatedly (once or twice a second) until RPMs got above 3000.

 

Finally, my car was also relatively difficult to get going smoothly from a stop in 1st. We all know the clutch is hard to modulate given its lack of feel, but with the sticky throttle plate it was difficult to modulate the gas going from no throttle to light throttle. I would push the pedal a little, get nothing, push a little more, get nothing, push a little more, get 2000-2500rpm, stink the clutch, etc. This was not pleasant in city stop and go traffic. Since the throttle plate replacement, it is much easier to consistently engage smoothly at 1000-1200rpm.

 

If my car wasn't actually stalling, I doubt my stutter would have been fixed. My car did this from day one, although the stall only happened once I hit my first winter. I don't know how common this problem is, but it sure sounds like others are hitting a stutter similar to mine. I understand there are other stutter/hesitations others complain about higher in the RPM band, but I never had those. I used to loathe the 2300-3000rpm band when driving gently (in traffic), and used to avoid it. Now, I no longer notice it at all.

 

--Lee

I've been wonderng about the throttle body myself lately. I dont really trust the drive by wire, and loss of power and rich running would indicate that its not getting enough air.

 

My other thought that its a sticky injectors doing about the same thing.

 

Either way, I want to flush teh system with some Seafoam and see how it responds.

Thanks ilh,

I was never sure if I really had the studder, but I definatley have the trouble getting into 1st gear, and I have also seen the RPM drop at idle(it almost stalled once or twice). I sometimes had the bucking, but I thought it was me. It happened both stock and stage1. I just flashed stage2 last night, so I have a new set of operating conditions to get used to:)

I will be keeping an eye on how the throttle is responding to my foot.

Try shifting from 1st to 2nd to 5th around 25-30 mph, youll clearly get the same studder, if not a stall.

That's not the "studder" (where did that misspelling come from btw?) we're talking about, that's your poor engine being lugged!

Hi all, has anybody opened up the intake to see if their butteryfly has some sticky substance gumming it up?

 

In a turbo car one source could be oil from the turbo.