Hesitation Issues with 2010 Outback Limited 3.6R

[rpr]

I test drove two different 3.6R's before pulling the trigger on one. The first one had a terrible hesitation when accelerating from low speeds. Driving through a parking lot stop and go (on purpose) was awful (a full second delay before the engine responded).

The second one I test drove was much better, but it still has a significant hesitation when accelerating from low speeds (i.e.: 1 to 5 mph), but it was tolerable, not very noticeable unless you were looking for it, and the vehicle performed superbly in all other regards.

The 4 cyl just didn't have enough power for us so I purchased this second 3.6R feeling that the hesitation was almost certainly a PCM programming issue related to the "drive by wire" that Subaru would almost certainly update (they have already released some updated programming for another issue related to low power when driving in reverese up a hill).

The only other similar posts that I have seen refer to a "sensitive pedal". That is either a different issue or misidentification of the same problem.

Anybody else notice this hesitation when accelerating from low speeds?

[westie]

Yes, the pedal on my 3.6 seems to be a bit sensitive from a stop. Seems to be worse when the engine is cold.

Not as bad once the engine has warmed.

[tschauer]

I have driven two 3.6Rs and both were speedy. I am absolutely speculating here but is there a chance the electronically engaged parking brake was on? I've read the brake does not automatically release unless your seat belt is on. Don't be offended by my question as this new electronic parking brake is new to all of us....

[heyandy]

I have a 3.6R, and have noticed the "pause" you mention, and you are correct, it is always from a very low speed (i would say under 10mph, but your under 5 might be correct)...

I have also noticed it is always when the engine is cold... As one of my other posts has noted, I have noticed I get a "long" blue coolant light once in awhile... But during the "pause" the light is not on..

I am going to try and pay more attention to this and report back...

[rpr]

Thanks for the replies guys. The parking brake was not on...and yes it is quite a new feature that takes some getting used to. I really feel its a PCM programming issue and I have to think/hope that Subaru will come out with an update.

My 3.6R is "speedy" as well, as one poster noted above, but its performance at speed does not seem to be affected by this issue which is limited to accelerating from LOW speeds.

I think this is contributing to the feeling that it has a "sensitive pedal". At low speeds if you depress the pedal an inch or two, it does not immediately accelerate. If you are very conscious of this, you tend to subconsciously think well maybe I didn't press hard enough and I didn't actually move the pedal, so if you are quick to expect your vehicle to respond, you push harder.

This all results in an intent to accelerate gradually but you shoot out into traffic because you overcompensate for the hesitation with too much "pedal push".

Lets hope Subaru fixes this. Otherwise...great vehicle!

[tk54911]

Interesting. I have what sounds like the exact same problem, only mine is a 2007 2.5i. I was here looking for ideas when I found your post.

I wonder if yours also does the same thing as mine. I tried this when I was trying to figure out what was causing the hesitation: put the car in park and "punch" the accelerator (I push it far enough down that if I leave my foot on the gas pedal, engine runs at about 4000RPM).

My foot is back off the accelerator before the engine actually responds.

Slow, smooth pressure on the gas pedal and everything is fine, driving or in park.

New plugs and air filter.

Any thoughts appreciated. Thanks!

[BlackTrac]

The OP in this thread is on the right track. The hesitation is very apparent on a cold engine especially the 3.6 R. I spoke to some Subaru techs and we agreed that it is a suspected PCM issue where the PCM is constantly recalibrating air/fuel measurements under certain engine temperature parameters. Basically, when you hit the gas....the PCM thinks about it for a moment either because it doesn't agree with the input, or because it is receiving conflicting information from a sensor or two. It goes into a "ignore" mode temporarily and releases a string of default information to the intake and fuel injectors. That's why no matter how far you hit the accelerator, you will get the exact same hesitation. From there once the car starts rolling, the parameters change, the sensor input changes and the PCM recorrects the information based on the drive-by-wire information received from the driver. So if you hit the accelerator lightly, it'll hesitate and then roll forward gently. If you hit the accelerator hard, it'll hesitate the same way, and then launch forward like you just got nailed by a semi from behind.

My mother's 2004 Audi A4 1.8T does the exact same thing and was corrected with a PCM reflash. Unfortunately the reflash software was released in 2006 and was NOT covered under warranty.

I think we gotta wait for a bit....but rest assured, Subaru will come to know of the problem if they don't already and will be working on it.

[fosto]

I've noticed this on my 3.6R as well. Definately unrelated to the hill-holder electronic parking brake feature as I have left that turned off. My guess was that it either had to do with the drive-by-wire as described here or I was catching the transmission in mid-shift. Now I'm more convinced that it is the drive-by-wire as this sort of symptom seems to be common even in other makes.

I don't think it has been any more pronounced when cold. Mostly it does it in "slow and go" driving. For example, making an almost complete stop at a stop sign then lightly hitting the gas will cause it to hesitate. I've learned to give it a second rather than follow my instinct to push harder only to end up rocketing down the block.

[rpr]

Thanks for the feedback guys. Hopefully Subaru will fix this. They already came out with a TCM update (tranny programming file) for an issue where the 3.6R has low power when ascending an incline in reverse.

[mattski]

Test drove the 3.6 Ltd. today. From a stop, it is really imperceptible (maybe 1/10th of a second). From a rolling "almost stop" it was more like 3/10thsof a second. If I was looking for it, probably would not have noticed.

Compared to my '02 Bean, it is much quicker in the first second of travel even wuith the slight lag... as the Bean takes about 1/2 second to find any sort of torque (although it is moving from the moment you touch the pedal ), while the 3.6 is like a frenzied bull once it kicks in. Again, will not bother me at all. I had a 2001 Turbo Passat, and that thing hung up for almost a full second - that was annoying as Heck and dangerous! The upside was that I sold it for my first Subaru and now I am hooked!