Sudden loss of power

Tnate · Post by **Tnate** » Wed Dec 26, 2007 5:11 pm

In Reference to a 1994 Subaru GX Sationwagon. Stock standard, except for a spring suspension conversion.

Alrighty, Ill try and explain this as best I can...
Lately when I have been traveling at high speed, as on a freeway, I get a sudden loss of engine power.
I'll be happily driving along when the car will start to slow down. As I push in the accelerator, there is no speed increase, and when I engage the clutch, the revs drop to 0 rpm.

I pull over and try to start the car, and the starter sounds like it is struggling to turn the engine over. Quite a disconcerting sound.

Wait 2 mins, car starts perfectly and will drive at highway speeds for the rest of the day without a hitch. Any ideas?

I dont believe its the fuel filter, as I can keep driving once the first 'breakdown' has been overcome.

The only error code I get is engine 02 sensor.

This has happened pretty much every time I start driving on the freeway, but as I said, once it's done, the car drives beautifully.

I'm baffled...

AndrewT · Post by **AndrewT** » Wed Dec 26, 2007 5:41 pm

well....call me stupid....but I think you're O2 sensor might be faulty...

Post by **Alex** » Wed Dec 26, 2007 6:01 pm

DEFINATELY!!

alex

Tnate · Post by **Tnate** » Wed Dec 26, 2007 7:33 pm

I do now feel pretty stupid, I just wasn't sure why it would go away just as soon as it started. Seemed a bit strange to me.

AndrewT · Post by **AndrewT** » Wed Dec 26, 2007 7:52 pm

Perhaps the sensor is just intermittently faulty, and kindof works again after the ECU is turned off and on again (switching the car off and on).
It's definitely the first place to look, brand O2 sensors can be had for less than $40 and its a 5 minute install. Even if it doesnt turn out to be the problem they are a good thing to have spare anyways.

Subafury · Post by **Subafury** » Wed Dec 26, 2007 8:00 pm

AndrewT wrote:Perhaps the sensor is just intermittently faulty, and kindof works again after the ECU is turned off and on again (switching the car off and on).
It's definitely the first place to look, brand O2 sensors can be had for less than $40 and its a 5 minute install. Even if it doesnt turn out to be the problem they are a good thing to have spare anyways.

i wouldnt be so sure on that price andrew. i remember looking some up recently and they were far more expensive than i thought. like over $100 i think.

EDIT: sorry i may be wrong i thought this for for an L series. my bad

AndrewT · Post by **AndrewT** » Wed Dec 26, 2007 8:10 pm

$38.50 delivered from an Ebay store is what my buddy Luke paid for one for his WRX recently (was similar price for a Lib one I think). But I think theres some horrible prices around too, probably from Subaru themselves would be quite high.

Post by **Alex** » Wed Dec 26, 2007 8:21 pm

fuel filter could be abit suss as well...MAYBE..

alex

littlewhiteute · Post by **littlewhiteute** » Wed Dec 26, 2007 9:50 pm

I don't know Subaru electronics, but if they engine loses power to this extent and then sounds bad while cranking, sounds like the ignition timing is going out of whack for some reason. ECU issue? And then doesn't do it again for the rest of the day? Won't be a fuel filter either. And I'll say the O2 sensor code is a result of another issue, not the cause. But for what it's worth, may as well change it, especially if it's done more than 80000km.

SUBYDAZZ · Post by **SUBYDAZZ** » Thu Dec 27, 2007 1:15 pm

Is it throwing you a code? Try checking fault codes in the system. There should be a thread around here showing you how to do it, What month compliance date in 1994 is it, GEN1 series 2 or a GEN2 Liberty?

It could be a combination of 2 problems. Then crank angle sensors are susceptible to heat-sink from the motor and if you stall in hot weather or when engine has been working hard, it may well not let you start then engine straight away. Usually wait 30 seconds or more and it will be right. The first part though definitely sounds like a fuel or ignition problem - it's just finding what it is that will be the tricky bit.

Matatak · Post by **Matatak** » Thu Dec 27, 2007 2:01 pm

hmmm good idea check codes....owait SUBYDAZZ he already says the only code is the O2 sensor

lol(no offence meant there)

sounds electrical to me. fuel filter or O2 sensor i cant see causing this.

it wuld be a Gen2 Lib wont it?

Gannon · Post by **Gannon** » Thu Dec 27, 2007 2:07 pm

An o2 sensor wont stop the engine, if it fails, the ecu will simply disregard it and operate in open loop mode. The most it will do is affect your fuel economy a little.

Id replace the o2 sensor anyway, especially seeing its 13 years old.

When you check the codes, are you checking current codes or stored codes?

Try checking codes immediately after it happens.

SUBYDAZZ · Post by **SUBYDAZZ** » Wed Jan 09, 2008 9:46 pm

Matatak wrote:hmmm good idea check codes....owait SUBYDAZZ he already says the only code is the O2 sensor lol(no offence meant there)

LOL, way to pick up on that, missed it

None taken.

madmat · Post by **madmat** » Sun Jan 27, 2008 12:50 pm

i had a similar problem to this and it was the Air Flow Meter.

SUBYDAZZ · Post by **SUBYDAZZ** » Wed Jan 30, 2008 11:35 am

Tnate, did you get this problem sorted?