RPM spike when getting out of gear

[WagonGuy]

This apart from the other power loss issue I'm having right now has been happening for a while, actually, since I remember. It doesn't happen all the time, every time, but sometimes when I change grears (~3500 - 4000 rpm), right after I press the clutch and let the gas pedal off, the rpms jump up another 500-1000 rpms and then normally fall down.

That doesn't seem normal. Has anyone else experienced something like that?

[AsILayDying]

Well I am interested in the answer or suggestions to this cause I experience this as well. I always think maybe it was me leaving my foot on the gas to long so when it happens I try it again to make sure to take foot off before even touching clutch and it still does it. Same RPM area as well. Doesnt happen all the time but frequently enough to not be right. Hope someone knows an answer......

[EvoEatr]

What year/model is the vehicle? There is a reprogram available for the newer model outback/legacy models for this exact same concern.....

[WagonGuy]

What year/model is the vehicle? There is a reprogram available for the newer model outback/legacy models for this exact same concern.....

Mine's a stage 2 05 wagon and AsILayDying's is a stage 2 04 sedan.

And I think we are both pretty much 'reflashed'

[AsILayDying]

Yep, reflashed running stage II Cobb map. 04' WRX Sedan. Wonder if anyone has an idea cause I dont want to bring it to subaru. They will just tell me they cant replicate the problem and to bring it in when it does it again. Problem is it doesnt do it all the time. So any help ideas or advice would be helpful

[Lavid2002]

HEYYYY!!! I was just thinking about this the other day...heres my theory. The turbo is pressure fed into the intake right? When you let off the gas the engine is still cycling....so although the engine isn't getting fed fuel and it doesnt have a power stroke it is still being fed pressurized air that makes the engine rev up a lil....

Im very very new to cars so this is probably very very wrong...hahaha but thats my n00b theory. Interested to see what causes this too.....

P.S. I'm BONE stock...I just have a screen in my hood scoop protecting my OHIC thats it

[Donkey]

It's normal. Some say it's the ECU and some say its the turbo. I know it generally only happens to me under light boost. Under vacuum or heavy boost it doesn't happen. I read some info on NASIOC that explained it but I can't find it now.

[WagonGuy]

HEYYYY!!! I was just thinking about this the other day...heres my theory. The turbo is pressure fed into the intake right? When you let off the gas the engine is still cycling....so although the engine isn't getting fed fuel and it doesnt have a power stroke it is still being fed pressurized air that makes the engine rev up a lil....

Im very very new to cars so this is probably very very wrong...hahaha but thats my n00b theory. Interested to see what causes this too.....

P.S. I'm BONE stock...I just have a screen in my hood scoop protecting my OHIC thats it

It only happens under a moderate boost of -2 to 5 psi so I don't think it's enough pressure to really propel the pistons. Besides, the BPV is supposed to take care of the extra air pressure and recirculate it.

It's normal. Some say it's the ECU and some say its the turbo. I know it generally only happens to me under light boost. Under vacuum or heavy boost it doesn't happen. I read some info on NASIOC that explained it but I can't find it now.

Only under low boost and only randomly, every time, all the time.

Another one of those things that makes a Subaru, a Subaru

[AsILayDying]

Ok Im gonna wake up a semi-old post. I have been experiencing this RPM spike after cltch goes in to shift to next gear if I shift at 3500 to 4000 it skies to like 5500 and then very slowly settles to like 2000 or 2500 which is extremely irritating. It only happens every now and then, and when it does happen it just magically dissapears like there was never an issue. Please some one hopefully an idea of what this could be. Thanks

[wrxtreme06]

i was always under the assumption that when your RPMs jump up like that, it means your clutch is on its way out.

[Donkey]

That would be the tale tell sign of a worn clutch.............

[AsILayDying]

Well I am almost 10000000% sure its not a clutch issue being that I just had my clutch replaced by Subaru a month ago. Its not while driving. Its while the trans is not engaged, out of gear sitting in neutral. Normal driving shifting from 2nd to third, let off gas push in clutch and RPM's sky, then settle down to 2500 to 2000 and sit there and sometimes rise for no reason. Hope this helps.

[Donkey]

Could be the cruise control cable or vacuum leak. Diagnosing vehicles over the interweb isn't the easiest thing...................

[AsILayDying]

I understand that its almost impossible to give perfect advice or help, but I appreciate the advice on what to look at or what to check so I will check the CC cable and for vaccum leaks tomorow after my uppipe gets installed. Thanks for help, by the way, last time I had the RPM spike it was because of a clutch and you were right. But that was a completely different spike, I could tell it was slipping. Again thanks for the help.

[WagonGuy]

Well I am almost 10000000% sure its not a clutch issue being that I just had my clutch replaced by Subaru a month ago. Its not while driving. Its while the trans is not engaged, out of gear sitting in neutral. Normal driving shifting from 2nd to third, let off gas push in clutch and RPM's sky, then settle down to 2500 to 2000 and sit there and sometimes rise for no reason. Hope this helps.

What happened to your old clutch?