Hesitation / loss of power - 2010 WRX

[soobie]

Hello members,

Recently, I've noticed once boost is up past 3k, it seems power has slightly been reduced. It feels like I'm feathering the gas but it's always WOT. I've been using 92+ octane. The car is 100% unmodified, 25,000 kms (~14k miles). It's being dropped off at the dealership Wed, but would like to get some input as to what may have caused this loss of power.

No codes, no smells....

I also know it's not pyschological (some people say you get used to the power, and crave more lol)

Thank you!

[TeleMan]

Given that your car is relatively new, I would guess it's one of two things:

1) Fuel injector jets might be a little clogged. Do you run a bottle of cleaner through the fuel system every 3,000 miles or so? If not, I recommend it.

2) Air filter might be dirty. Simple to change.

When you stomp on the pedal and don't get the turbo boost you experienced when the car was new, it's probably a fuel/oxygen ratio issue. Try the simple and inexpensive trouble-shooting first. If the problem persists after the two ideas above, then maybe something more serious is wrong with a sensor somewhere. Your car is still under OEM warranty, so it's shouldn't drain much of your wallet.

Good luck.

[soobie]

Thanks for the tips. I haven't run any cleaner as of yet, I've only had the car for roughly 1000km (400 miles). Thus, I don't know what brand gas the previous owner (who kept it literally in MINT shape), used.

I'll try the cleaner now that its a good time as the tank is nearly 1/4.

The air cleaner WAS dirty, but I was experiencing this issue a week after I changed it.

Thank you

D

[teflon_jones]

Could be any number of issues. I'd think of a dirty MAF or a boost leak first.

I'm always curious why people under warranty worry about things like this though. If anything, wait until the dealer gives you a diagnosis and then post back what they say.

[soobie]

Could be any number of issues. I'd think of a dirty MAF or a boost leak first.

I'm always curious why people under warranty worry about things like this though. If anything, wait until the dealer gives you a diagnosis and then post back what they say.

I just wanted a few more opinions before I took it in. Not worried at all

I'm also going to try the MAF cleaner tomorrow

[TeleMan]

Could be any number of issues. I'd think of a dirty MAF or a boost leak first.

Teflon,
I'm not challenging your comment. I'm trying to learn. If the MAF sensor was dirty, would it show as a problem code on an engine analyzer? Would the "Check Engine" light on the dashboard? Where is the MAF sensor on the WRX? Is it easy to clean as a DIY task?

Thanks.

[TeleMan]

Please disregard. I searched and found the answers to my MAF questions.

[soobie]

It's going in tomorrow and I'll let you guys know what it was.

[mudferret]

I just wanted a few more opinions before I took it in. Not worried at all

I'm also going to try the MAF cleaner tomorrow

Not sure how similar the 2010 MAF is to previous years but make sure to clean the actual MAF sensor (hidden up in the tube) rather than just the IAT sensor.

[soobie]

Good idea mudferret.

Subaru dealership suspects an ECU problem, but will connect a boost gauge next week to confirm.

Now that I have it back, I'm going to clean the MAF and IAT.

D

[teflon_jones]

Good idea mudferret.

Subaru dealership suspects an ECU problem, but will connect a boost gauge next week to confirm.

Now that I have it back, I'm going to clean the MAF and IAT.

D

Be careful what you do with a car under warranty. If they see the screws on the part have been removed, they may deny things. Just let them figure it out rather than trying to fix it yourself.