BG Auto: Low/no power at low RPMs

[Pharaun]

I'm driving a 2004 Subaru Impreza WRX 2.0L Turbo and as the title says I have low/no power at low RPMs. I really have to rev it up to get it moving, but once I get up in the 3-4k RPM range it's fine. I've replaced the air filter and the spark plugs, but I'm wondering if anyone has some ideas as to what it might be before I take it in to my mechanic to get it diagnosed.

[liggy 0]

is the pick up always at 3k+ rpm? if there isn't anything weird sound/smell/feel.... something is loose. (maybe throttle cable)
could also be the fuel pump, but i highly doubt that.

this is a manual tranny, does it shift smoothly? if not then it's probably your clutch. happen to me back in the day when i got my used car. i could take it to redline n get up to only 20mph. when i took out the clutch, that shit was gooooOne. worn out clutch just wont grab.

[Isiolia]

Have you been driving the car for a while and this is a new issue, or are you coming from a different vehicle? My general impressions of Subarus (keeping in mind I own one) is that you do need to give them some revs to get them moving. I know another guy who has a WRX, and he has the same observation/complaint. They're not gutsy V-8 engines (you need revs to get your turbo spooled up too), and it takes a bit to get the AWD drivetrain moving.

That said, way back in the day I had issues with bogging in my Dodge Shadow, and it was an O2 sensor issue. Could be something to do with it.

[Pharaun]

It's a new issue, I've had the car for a little over a year and this has only been happening for the last couple of months. Yes, it is a manual tranny, but everything is running fine no weird sounds/smells etc and it shifts fine.

I'll check the O2 sensor, but the check engine light isn't on so I don't think it's a sensor/major issue that would cause it to come on.

[Heavencloud]

You might try asking or searching on nasioc to see if it's a common problem for the 2.0l engine. Probably only seems fine at 3-4k rpm because the turbo is kicking in? Somethings definitely wrong if you have to rev up a lot to get going.

[FNH]

when swapped the plugs what did they look like? and did you change the wires and coil packs? When was the last time the fuel filter was changed? tons of things could be sapping power at low rpms, does it make a sound once you reach a certain rpm range that produces power or does the car lurch a bit when you hit that range?

[Alduere]

2.0L WRX's have VERY low power on low rev's. That's why they changed it to 2.5L.

It's hard to tell how LOW your power is but from personal experience the difference between a 2.0L and a 2.5L before turbo kicks in is incredible.

[Max™]

Do you notice a change in the sound at around 3k rpm when you have the clutch depressed, in neutral, and in the first few gears?

Check to see if it sounds particularly different in any gear, or if it always generally sounds the same. Is the pickup only from a standstill, or is it always slow even when downshifting at speed? Have you done anything particularly stressful, drop the clutch at high revs for quick launches, etc?

If the engine itself sounds the same, and seems to show no change depending on the gear you're in, it could be clutch slippage, if it's weirder in low gears than high gears it could be damage in the tranny, the diff, etc. Do you notice any particular revs where the sound catches a bit? Does it seem like the turbo isn't spooling as easily as usual? It could be a turbo bearing, or gears that are getting sloppy/gunked if it seems to take more work to get it breathing.

The engine normally takes a bit to build up the grunt, but if it's changed dramatically enough as you are saying, and you haven't noticed anything odd in the tranny feel, I'd look at the turbo plumbing/bearings, oh, and the exhaust as well, it might not be breathing out the butt as smoothly, taking more grunt to get it flowing could sap power like this too!

http://forums.nasioc.com/forums/forumdisplay.php?f=37

Stock 2.0L Turbo WRX forum.


Incidentally, I love these grumbly little engines.

http://www.youtube.com/watch?v=Mu2QCMRtCp0

[Pharaun]

Thanks for all the advice, now I have a few other things to check out this weekend. As for the spark plugs, they looked fine when I changed them, no oil or excesses corrosion to indicate that it's running rich. I changed the wires/coil with it since I bought the car used and had no idea when they'd been changed last.

[jmc]

+1 for checking out nasioc forums. Probably the best site for your question, as they have a dedicated forum to the 2.0l engine.

Not to mention, if you start posting around in the regional threads there.... maybe someone nice enough can come by and check out the issue for you. When I had a problem with my '07 impreza a guy I've bumped into at subaru meets came by to check out my problem for free after work. (Subaru tech at a dealer down the street from me)



*edit*

Well, not really free..... but fee was a pizza and some beer while he was looking/working on it lol

[Heavencloud]

Well, not really free..... but fee was a pizza and some beer while he was looking/working on it lol

That's pretty much always the deal (beer/food), sure as hell is cheaper then a shop though! Regional forums over there are great :D