26 replies to this topic

[Scooby]

OK so I have a 97 suabru liberty rx DOHC has had new head gaskets and piston rings about 40,000 kms ago and the heads were also rebuilt. Just recently my car has lost power and feels like the fuel to air mixture isn't right.
What happens is the car will start no problems and has a stable idle but when driving lightly bogs down pretty badly seems more obvious under load like going up hills. If i drive the car harder it seems to stop the car bogging down but is still quite hesitant with the power delivery.

Things that i have tried already, changed the throttle position sensor,crank angle,cam position sensor,knock sensor,o2 sensor, the spark plugs look fine, i've tried different leads.

So at the moment I'm unsure about what to try next apart from taking it in to Subaru which seems like my next step, if anyone else has any ideas as of what it could be I'm open to suggestions.

thanks

[alexGT]

checked fault codes?

[Scooby]

not getting a check engine light

[acres]

Low fuel pressure?
Poor compression?

[Nicko_]

How many tanks of fuel have you gone through??
Could it be just a shitty fuel??

[Grant]

AFM?

[Dylan]

Did you say you have swapped the air flow meter, or cleaned it ?

[Scooby]

just changed over the air flow meter and o2 sensor and no change, I don't think its compression because when i was driving then the car goes ok and then it looses a lot of power quickly when i put my foot down past a certain point. I can drive the car very softly and slowly and it seems ok but as soon as i put my foot further down to accelerate it really struggles to take off. Also the car revs freely its just under load that it can't perform.

Can you have intermittent problems with your fuel pump or fuel pressure regulator?

[Scooby]

Did you say you have swapped the air flow meter, or cleaned it ?

Have cleaned the one that was on my car and no change then I just put a spare one that i had in with no change, I didn't clean the spare one before it went in but it didn't look dirty

[Dylan]

If you've got some contact cleaner it might be worth giving them a spray and trying.. you never know !

[RX25SE]

Sounds like you've tried all the basics.

Cam timing? Weird I know, but could it have jumped a tooth?


Edit: try reading codes anyway.

No splits in the pipework between AFM and throttle body?

[Start]

Faulty Cat?

My old car died going up hills, and lacked heaps of power cause the cat collapsed.

[RX25SE]

^^^ this is worth a look.

[Scooby]

that sounds like a good idea, I had this problem a few months before and just went away but now its a lot worse. Just went for a drive to the shops then and the car was struggling at low rpm but at about 2,500-3,000 rpm the engine would accelerate again it would still struggle but was a lot better at higher rpm, does that sound like a collapsed catalytic converter?

[RX25SE]

Blocked cat should be worse at higher RPM.

Still worth a look.

[camoshop]

hey ant , could be an idea to swap the zorst from the white rx and see if your car runs better , before you sell it , if its no too much effort

[Scooby]

not a bad idea a lot of work though

[RX25SE]

Cam will help you.

He has a world of experience with exhausts.

[camoshop]

not a bad idea a lot of work though

if you could get a hold of some car ramps would be easier to work underneath

[acres]

Can you have intermittent problems with your fuel pump or fuel pressure regulator?

Try disconnecting the vacuum line on the pressure regulator while the car is idling, if there is no change in rpm then it is probably faulty. The engine speed should change again once you reconnect the vaccum line.