91 Legacy L throwing multiple codes

[CarnageMC]

My suby is a 91 Legacy L Wagon and the past couple weeks its been having a lot of problems.
Runs fine when first started/cold but when the engine gets to operating temp it starts having trouble and throwing codes.

Problems are:
Idles at 400 (idles at a normal 900ish when cold)
Idle will randomly surge from 200-1000 over and over and will want to die
Very sluggish under 3k rpm

The codes thrown are:
11 crank angle sensor

22 Abnormal voltage produced in knock sensor monitor circuit

24 Air control valve inoperative (Abnormal signal produced in monitor circuit)

31 Abnormal voltage input entered from throttle sensor

32 Oxygen sensor inoperative

35 Solenoid valve inoperative

Any idea what the problem could be? Possible fixes?

[wtdash]

Hi and Welcome to the BBS,
I'd replace your CTS (coolant sensor) and your knock sensor (I'd bet it's cracked) 1st.

Clear the codes, if possible, then see what comes back.

GL,
Td

[Legacy777]

Yeah, I'd recommend clearing the codes and then checking again. Instructions for clearing the codes are on my site:

www.surrealmirage.com/subaru/engine.html


I'd also suspect the coolant temp sensor may be the cause, but it's good to clear the codes and check to see what comes back.