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"Studdering" Fix Released


Opie

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It doesn't, but tuning for ultra low emissions may result in "driveability" shortcomings, such as stuttering/hesitation.

 

ULEV, is exactly the problem. This is why the issue doesn't exist on the WRX & the STI. The STI is tier1, & the WRX is LEV. Both don not have the pre-catylitic coverter in the up-pipe as in our cars, unless you remove it like I did.

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stuttering like an Escort with a blocked fuel filter and a bad tank of gas. Could the problem be something other than the ECU if a reflash doesn't fix it?

 

Totally agree - I was very annoyed at having to spend $650 on an AP to get the car to run half decently after spending $28k on a car (btw the new AP map versions 1.10 are quite a bit better)

From reading the various threads on this topic, there are clearly different severities of this fault, from none at all to the Escort with the blocked fuel filter, bad gas, burnt out exhaust valve and a broken plug. I think drivers who do not have the problem or have a mild infection would be shocked if they drove my car or yours. I think this explains why some people think we are blowing it out of proportion.

Since running with the AP, I have fixed the blocked filter, exhaust valve and plug, just have the bad gas left. I am hoping the next map release will get rid of that too !!

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ULEV, is exactly the problem. This is why the issue doesn't exist on the WRX & the STI. The STI is tier1, & the WRX is LEV. Both don not have the pre-catylitic coverter in the up-pipe as in our cars, unless you remove it like I did.
This is not an emissions issue, removing the uppipe may change the behavior slightly, but it does not eliminate the bucking. As I was trying to hint at earlier, a car the runs poorly is a car that generates higher emissions. As in racing, the path of most efficiency is the smoothest. This emissions reason is just a bad rumor that keeps getting passed around. One of many in the "make annoying customer go away" bag of dealer tricks.

 

The program the ECU runs is unrefined by design, messing with the map can smooth out the emergent behavior somewhat, but it's just putting a patch on the symptoms.

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my studder fix.....shift at 3500-3700rpm

run 93.

Noticed mine doing it too.

But this is my first turbo car.

Changed my driving habit.

My STI didn't do it, but I was always running the beoch hard.

Now I have a Tribeca. WIfe has legacy.

Not worried 20g and Front Mount coming soom.

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This is not an emissions issue........ As I was trying to hint at earlier, a car the runs poorly is a car that generates higher emissions.....

 

I guess you weren't around in the 1970s, when new stringent federal emissions laws took effect. Cars of that era ran much cleaner than earlier model years, but ran poorly as a consequence of being cleaner.

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I'm calling this...

 

B. Top tier fuels are not necessary, the car is sold in the NA market to run on 91 octane, it must be designed with enough tolerance for the available gas. Yes, "tolerance" this is called "engineering". Nevermind the gas issue is bullshit, actually I'd believe the car should run smoother if you put 87 in, as the ECU is in full panic mode and pulling back timing to it's lowest levels. Not to mention even with the 91 requirement many of us are running 93/94 octane.

 

To be honest, I thought the car felt like it was running rich during the medium throttle 2.5k-3.2k zone. Backing off the gas slightly smoothed it out. Plus, it was always far worse after the car had been sitting overnight, when it runs on a richer "cold" map anyway.

 

So I decided to use something that I thought might ignite a bit quicker than the 93 I'd been using. 91 is not available in my area.

 

A tank and a half of 89 later, and the stutter is almost gone. 3 tanks later, I'm noticing no power loss and a much diminished stutter. I really think the thing just runs pig rich on medium throttle applications in that 2.5k-3.2k zone.

 

So 89 has helped my stutter. FWIW, YMMV, etc.

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ULEV, is exactly the problem. This is why the issue doesn't exist on the WRX & the STI. The STI is tier1, & the WRX is LEV. Both don not have the pre-catylitic coverter in the up-pipe as in our cars, unless you remove it like I did.

 

WRX's do have a cat in the uppipe, at least throught the 2005 model year. STi's do not.

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To be honest, I thought the car felt like it was running rich during the medium throttle 2.5k-3.2k zone. Backing off the gas slightly smoothed it out. Plus, it was always far worse after the car had been sitting overnight, when it runs on a richer "cold" map anyway.

 

So I decided to use something that I thought might ignite a bit quicker than the 93 I'd been using. 91 is not available in my area.

 

A tank and a half of 89 later, and the stutter is almost gone. 3 tanks later, I'm noticing no power loss and a much diminished stutter. I really think the thing just runs pig rich on medium throttle applications in that 2.5k-3.2k zone.

 

So 89 has helped my stutter. FWIW, YMMV, etc.

 

 

When I talked to the service rep last time, he mentioned that they previously thought the car was running lean, but SOA techline said the problem

is because it is actually too rich. I'm no mechanic so I don't really know what that implies.

 

My car seems to run a bit better with 93 Shell V-Power than my previous choices of gas.

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My car seems to run a bit better with 93 Shell V-Power than my previous choices of gas.

 

I always ran Mobil 93, but they left my area so I switched to Sunoco 94 and didn't notice any difference besides a thinner wallet. This week, I tried Shell V-Power 93 and the car seems to really like it... that or it's placebo.

 

WRT to the stuttering, I guess I'm lucky that I have an early build and the stuttering seems to have stopped since I passed ~3k miles.

 

I hope those stuttering and bucking get it sorted out soon. :(

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Just checked the build date of my car and it is 03/05, so this means that my car probably has some sort of updates already..but it's hard to say. I still notice the surging, but I'd hate to think that mine is less than what others are experiencing. If that's the case, then wow...that was a pretty big screw up on Subaru's part.
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Just checked the build date of my car and it is 03/05, so this means that my car probably has some sort of updates already..but it's hard to say. I still notice the surging, but I'd hate to think that mine is less than what others are experiencing. If that's the case, then wow...that was a pretty big screw up on Subaru's part.
I'm not kidding when I say "bucking"
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Well, it's the second day of cooler (70's) air here in Michigan and the bucking has vanished. We had a long stretch (3 weeks) of 90 degree very humid weather and it bucked the whole time. Drove it a bit yesterday and it was VERY mild. Drove her to work today and could not get her to buck at all. Oh and must mention how much faster she feels in this cool dry air. Love this weather...
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Yeah, yesterday in +100F on the trip computer, the car would buck on the highway when trying to pass someone and that's on the 5EAT.

 

Can't wait for winter, still StupidOnArrival have to get their act together and at least eliminate it on future Legacy models.

I keed I keeed
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dark_rex : the ECU tuners tune the actual A/F ratios and so they aren't depending on Subaru's stock A/F map to give them more fuel. Any power increases from the ECU tuners comes from raising boost, but correct me if I'm wrong.
I keed I keeed
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Hope this isn't a dumb question but how do I tell for sure that my car is acting this way? I have owned my 2.5LGT ltd for almost a month and put about 1500 miles on it. Can someone explain the behavior? does it affect most of these cars or only a small percentage? I ddi read through a portion of this thread but mostly people were talking about the problem in general terms and i'd like to be able to confirm or not whether my car is doing it.

 

 

Thanks

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Hope this isn't a dumb question but how do I tell for sure that my car is acting this way?

Thanks

 

If the other thread doesn't help, here's how I can get it to happen very easily:

 

Stay in 1st gear.

Accelerate a little past 2500 RPM (doesn't have to be quick).

Let off the accelerator and let it drop around 500 RPM or so.

Press the accelerator again and studdering shall commence.

 

Experiment with how hard you press the accelerator, and how far you let the RPMs drop. This happens in every gear, but it's very easy to tell in 1st. If I get it just right the car will go a bit crazy bouncing on its own for quite a while. I felt it happen in 5th today (the car just shudders at that speed). This also happens almost every time I downshift around 2600 RPM (most noticeable from 1st to 2nd).

 

Luke

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Count me in as a casualty….

 

My 05 GT/LMT is at the dealer today for its 15K service. My problems:

 

1. The nefarious f’n cooling fan on all the time.

2. Shuddering on acceleration, all gears.

3. Threw a CEL on my way to Boston Tuesday. Cleared itself the next morning??

4. Drivers door wiring harness rattle.

 

Do I get a door prize for presenting to the dealer with the most combined problems?

 

So the dealer (Maine Mall Motors, South Portland, ME) steps up with no BS. Calls SOA, and admits that there is a problem with the ECU, and my fan control switch, which should take care of all my problems when replaced………or will it?…..hmmmmmm.

 

So the absurd part of my conversation with the service manager comes when he asks me what grade of fuel I’m pumping into the car. Only the best, “93 Octane” says I. “Well” says the service manager, “my tech sniffed a sample of the fuel in your tank while performing your injector flush, and he thinks you got a bad tank of gas, which could also promote the acceleration surging you are reporting, you might want to change stations where you purchase fuel”.

 

Huh…..WTF……I didn’t know Subaru techs were trained in the fine art of olfactory vapor diagnosis. I’m envisioning one very high & brain damaged tech they keep in the corner just for this purpose!

 

Thought I’d share a funny!

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If the other thread doesn't help, here's how I can get it to happen very easily:

 

Stay in 1st gear.

Accelerate a little past 2500 RPM (doesn't have to be quick).

Let off the accelerator and let it drop around 500 RPM or so.

Press the accelerator again and studdering shall commence.

 

Experiment with how hard you press the accelerator, and how far you let the RPMs drop. This happens in every gear, but it's very easy to tell in 1st. If I get it just right the car will go a bit crazy bouncing on its own for quite a while. I felt it happen in 5th today (the car just shudders at that speed). This also happens almost every time I downshift around 2600 RPM (most noticeable from 1st to 2nd).

 

Luke

 

Luke - Thanks for the direct info. I checked the other thread and I think I can check it out - my only other question is that it seems to be affecting manual transmissions a lot more. My car is automatic and maybe it is harder to detect the "studder" with this transmission. Anywa, I will check it out later today.

 

Thanks

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