Just had service - new 2500rpm stuttering

Ive had my car for 60k kms now (stock), havent really seen much of a stutter between 2500-3000 rpm for a long time.

 

Just had an oil change/routine service.

 

I am wondering if maybe the dealer reset my ecu or something because now right at 2500 rpm there is a bad hesitation, where there is almost no power, then a rough jumpy stutter up to 3000rpms (seemingly only really in second gear).

 

Otherwise the car feels normal, except it seems a bit easier to rev match between gears.

 

I am wondering if the ecu was reset and is just relearning/unlearning or something any ideas?

Anyone?

Yes, most likely they reset your ECU.

Resetting your ecu won't do that. I've reset my ecu countless times.

 

They might have reflashed it. Did you check the invoice?

 

My guess is there is a small air leak somewhere in the intake. When they inspected or replaced the air filter, they may not have seated everything properly.

 

For me, after resetting the ecu, the most important thing is to get the AFR Learning back up. You can do this by driving with a steady throttle (not steady mph... constant throttle). You also need to do this for the high load region. I can usually do this by driving up a sloped freeway at about 70 mph with constant throttle. However, I've rescaled my MAF so I don't rely upon AFR learning anymore.

I drove around a bit at lunch.

 

It seems like the hesitation (pretty bad) happens more between 2000-2500, almost like no boost, then hiccups up a few hundred rpms, before all is normal above 3000rpms, seems to happen in most gears but most noticeable in 2nd.

 

So whats the consensus? A leak or just a relearning ECU?

 

Any way to tell for sure?

 

Thanks!

Just spoke with Subaru, they say they wouldnt have reset or reflashed my ecu.

 

Unfortunately they also cant see my car for almost a week.

 

Is it easy for me to check the filter if that might be the cause?

I would start by looking for the obvious.

 

First look around the entire air filter box and make sure it is seated. Then inspect the hose between the air box and inlet pipe. Make sure the pipe is seated against the stops and the clamps are tight.

 

Then look through the list of stuff that they inspected / replaced.

 

Really, the dealer should do this diagnosis for you. It sounds like they f*cked something up.

I would start by looking for the obvious.

 

First look around the entire air filter box and make sure it is seated. Then inspect the hose between the air box and inlet pipe. Make sure the pipe is seated against the stops and the clamps are tight.

 

Then look through the list of stuff that they inspected / replaced.

 

Really, the dealer should do this diagnosis for you. It sounds like they f*cked something up.

 

Thanks Ill take a look and see if anything looks out of order.

 

The problem is the dealer cant see the car for a week and already once today I was caught in the middle of an intersection with no power for a couple seconds(yikes).

Pay no attention to the red circles in this next picture. Now remove the electrical clip on the top of the airbox and unclip the two metal clips. The airbox will open in half and you can reposition the filter if it looks off.

 

http://premium.uploadit.org/cultofthejedi/intake-silencer-removal-002.jpg

Thanks for the pics. I just looked under the hood briefly (at work), it looks like the airbox could have been open a couple of mm if that would cause any of this, which I corrected. Ill check the filter when I get home if the prob persists.

Just went for a quick spin, I think that the airbox must have been open a little bit as now the rough hesitation seems to be gone for the most part, ill check more on my drive home to be sure.

 

Thanks for your help

Yeah, that would cause this problem. Pretty classic.

 

Don't forget to call your dealership and tell them how disappointed you are in their lack of pride of workmanship that they did not bother to double check something as simple as this. You should fill out the SOA report card too.