Any Fuel Injection gurus???

I need someone who is familiar with Subarus and fuel injection. Anybody out there??

1999 Subaru Legacy Outback, 2.5 auto.

I changed the oil and filter on my wife's car this morning. Drove it into the garage and up on the ramps like always. Checked the air filter and replaced it. New oil filter, and fresh 5w30. Went to pull out, and the wagon will start, idle at about 800rpm for about 5 seconds, then stumble and stall. It won't run at less than 2000rpm. To get it there, you have to start it, then immediately bring it up to over 2000rpm. Even at 2000rpm, it will begin to stumble and bog, and lose engine speed, and you have to pump the throttle, and coax it back up to speed again to keep it running.

I didn't disconnect the mass air flow sensor when I did the air filter, just removed the clamps and flex pipe between the filter housing and the intake. I checked to make sure the wiring was still connected and intact and nothing was damaged around the sensor. Doesn't look like there are any problems there. I disconnected and reconnected the sensor. Still ran the same way. The check engine light didn't come on, but I tried disconnecting the battery for several minutes to clear any DTC's. Still running the same. It seems like it is running in "limp" mode, because it won't idle, but will start every time, and runs OK at W.O.T.

I'm kinda stumped what to check next. If anyone has any ideas, or can even point me in the direction of any good resources, I'd really appreciate it. I've found a couple of Subaru forum sites, but they seem to get almost no traffic. Thanks.

Geoff Cameron

did you disconnect the battery BEFORE fiddling with the sensor? you may have bridged/shorted a sensor or two if you didnt...

Is the check engine light on? You could try bringing it to Advance Auto or Autozone to have the ecu codes checked for free.

Check the original post, the sensor was not disconnected until after the problem arose. At that time, it was disconnected and reconnected with the key off, and battery connected, just as a means of verifying it was a good connection. This had no affect on how the car ran.

I can't think of a reason why there would be a wire to the mass air flow sensor that was hot at all times, and would cause arcing/shorting, as stated in the first reply.

Also in the original post, the check engine light is not on.

Thanks for the info regarding a free scan at Autozone. I didn't know they offered that.

Geoff

There can still be a code if the CEL isn't on.

You can try disconnecting the sensor and starting the car to see if that changes anything.

These forums might be useful to you:
http://forums.nasioc.com/forums/
http://www.forumsubaru.com/