92 legacy idle problem (yeah another one)

[Slamngears5]

my 1992 legacy wagon AWD Automatic is idling high around 1250 rpm when its in park or neutral with no load it revs to 1250rpm then drops to 1100 rpm then back up to 1250 and drops back down and so on when i put it in gear the rpms drop to about 800 for the most part it drives fine except for when i keep it constant at about 2000-2300 rpm it does the same thing as above so i have to keep the rpms out of that range which is difficult in city driving does anyone have any ideas im at a loss right now

[Legacy777]

Can you provide any additional information as to when this first started happening? Was it a gradual thing, or did you just turn on the car and this happen?

 

Was there any maintenance or other work that was done around the time it first started happening? Is the check engine light on?

[Slamngears5]

Can you provide any additional information as to when this first started happening? Was it a gradual thing, or did you just turn on the car and this happen?

 

Was there any maintenance or other work that was done around the time it first started happening? Is the check engine light on?

 

it started all at once yes there is a check light on but this is my first OBD1 car and i am clueless on how to retrieve codes i just got the car a month ago and it set for a few months before i got it so i put some fuel injector cleaner in it along with an oil change plugs and wires a new air filter at first it had a rough idle then one day all this started happening so im clueless

[snowscooby]

I had similar idle problems in my car (97 impreza) and got an idle air control code. What you should do is get a can of ether (shouldn't be very expensive) and with the car running spray the ether on areas with gaskets or hose clamps that could be causing a vaccum leak. If there is a leak then the ether will be pulled into the engine causing the idle to spike (because your making the air fuel mixture ritcher). I ended up replacing two gaskets and it seemed to fix my problem.

 

When you do the ether test make sure and check each gasket several times from several different angles.

[Slamngears5]

yeah ive done the ether trick i even replaced my IAC and new gasket i cant find a leak anywhere that was my first thought also

[Legacy777]

Pull the codes from the ECU. The info on how to perform this is on my site.

 

http://www.surrealmirage.com/subaru/engine.html

[Slamngears5]

Pull the codes from the ECU. The info on how to perform this is on my site.

 

http://www.surrealmirage.com/subaru/engine.html

 

Thank you i pulled the codes (a 24,31,32,35) not sure how much its going to help me ive already replaced a couple of these parts im going to reset my ecu and see what comes back and go from there

[Legacy777]

Yeah, you're on the right track. Reset the ECU and see what codes come back.

[Slamngears5]

Reset the ECU and codes 31,35,and 24 came back im assuming code 35 isnt the problem so now i need to figure out what to do for the other two

[Legacy777]

Code 35 for the canister purge solenoid can cause some weird issues and not let other codes to clear. I believe this is due to an emissions thing. I would probably recommend replacing it, even if with a used one. You can apply 12v to the solenoid to test it. If you don't hear it clicking, it is bad. The other thing you can do is connect the green diagnostic connectors. It will cycle power to the solenoids so you can check them. The radiator fans will cycle as well as some of the other relays.

 

Code 31, I doubt that's a real problem.

 

Code 24, for the IAC valve may be causing your idle issues. Here's the diagnostic test procedure for the IAC valve.

http://main.experiencetherave.com/subaru_manual_scans/FSM_Scans/1992-1994_IAC_Diag.zip