Mechanics

ENGINE ACCELERATION STUMBLING

2000 Subaru Outback

Engine Performance problem
2000 Subaru Outback 4 cyl All Wheel Drive Automatic 130000 miles

Having a problem at take off, from dead stop I accelerate and the engine doesn't have the power it used to. Also, sometime ( not always) when maintaining speed say of 55 mph, the engine will do a stuttering or stumbling, like it's not firing correctly. I'put a new fuel filter in but that wasn't the problem. Any recalls out there? Any ideas? Thanks
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Jzontelli
August 19, 2008.



I have a similar problem with my 2001 2.5 at 185K miles. Reasonable starting from cold but stumbles BADLY during warm up and sometimes beyond. It starts and runs well when fully warm. Stumble and bog are very bad and pose a safety problem. Code indicates a misfire on three of the cylinders so I replaced the plugs which were clean but the gaps had opened up. No improvement. Thinking that a build up on the back sides fo the intake valve might be acting as a fuel sponge, I dosed the engine with ea Foam, which I have done many times with all of my vehicles and there was no improvement. The other code that appeared indicated a failed knock sensor. I have not replaced it simply because I don't want to spen the $100+ on a part that cannot be returned. This all feels like a fuel problem, rather than an electrical one as it feels like an oveerly lean mix during the periods of trouble. I am a bit familiar with soem of the Bosch injection systems and if I knew more about this one I would be looking for a failed warm up pressure regulator, but as I say I just don't know enough about these to make a call. BTW: I have been looking for a schematic for the injection system in general but have been unable to find anything useful. If anyone knows about same I would appreciate knowing where it is. Thanks, Jack

Tiny
Jackscars
Sep 24, 2011.
Please forgive the spelling errors in the above post. I am new here and hit the enter button before I could complete my spell check and then have not figured out how to edit things after posting them. Jack

Jack

Tiny
Jackscars
Sep 24, 2011.
Do you have a check engine light and whne was last tune-up performed

Lack of acceleration, chugging, hesitating********, bogging, misfiring etc. Could be caused by one of the following below

Oxygen sensor.

Catalytic converter.

Fuel injectors dirty/sticking.

Mass airflow sensor/Airflow meter.

Throttle position sensor.

Crankshaft position sensor

Knock sensor

Manifold absolute pressure sensor.

EGR Valve

Fuel pressure regulator leaking or defective fuel pump.

Fuel contamination.

Foul/defective spark plugs.

Open spark plug wires.

Ignition coil/Coil packs defective.

Incorrect ignition timing.

Cap and rotor.

Note: If it doesn't apply disregard it and keep testing.

Rasmataz
Dec 10, 2011.