I have a 93 legacy with the 2.2 and about a week ago the idle started surging (500-1000) and idleing really rough. It will even die sometimes when the car is just sitting. Another one of my cars had a simalar problem and it was the coolant temp sensor so i replaced that but it changed nothing. Any ideas would be great. The check engine light will go on at highway speeds but never stays on more then 30 sec's or so. I dont have a reader so i havent pulled the codes.

Thanks

David

The ever popular MAF or look for vacuum line issues....lots of threads on dealing with MAF issues, use "search"

Mine had issues with the IAC, get some seafoam down the vaccume line in there, and let it soak for a little while and it should get better. If its the IAC.

I have a 93 legacy with the 2.2 and about a week ago the idle started surging (500-1000) and idleing really rough. It will even die sometimes when the car is just sitting. Another one of my cars had a simalar problem and it was the coolant temp sensor so i replaced that but it changed nothing. Any ideas would be great. The check engine light will go on at highway speeds but never stays on more then 30 sec's or so. I dont have a reader so i havent pulled the codes.

Thanks

David

 

Pull the ECU codes

www.surrealmirage.com/subaru/engine.html

Pull the codes, but surging and hunting often means a failed O2 sensor.

 

Jack

David

 

Had the same surging problem on daughter's 90 2.2.

Swapped out the idle air control unit and all is well.

Wish I had thought of the seafoam treatment though.

rick

w. mi.

Though i'd let ya know how it worked out. I pulled the code #32 o2 sensor. Replaced that, still a bad idle. Started hunting for vacume leaks and found that the drivers sides intake manifold gasket had blown out, making one of the cylinder miss at idle, that probaly killed the o2 sensor. Replaced the gasket and now im running great. Thanks for the help and the info on how to pull the codes.

David