Need Solutions to '91 Legacy Trouble Codes

[rollor]

I just checked the Trouble Codes causing my Check Engine light to come
on (it's been coming on for years), and I had quite a few causes. I
was just wondering if anyone could describe the best way to fix each of
the problems (whether it's possible to fix myself or if I need to take
it in and whether the problem is even worth fixing since my car is
still currently running.)

The codes that I got ...

11: Crank Angle sensor
12: Starter Switch
21: Coolant Temp Sensor
22: Knock Sensor
23: Air Flow Meter
35: Canister Purge Solenoid
42: Idle Switch
51: Neutral Switch (manual transmission)

Parts I've found:
21: Coolant Temp Sensor: how hard is it to replace this?
22: Knock Sensor: doesn't seem too difficult
23: Air Flow Meter: expensive part ...is it worth replacing?

Questionable:
11: Crank Angle sensor: can't find this part
12: Starter Switch: do I need a whole new starter?
35: Canister Purge Solenoid: have only found 2 things close to this
(vapor canister and purge valve). What needs to be replaced or looked
at?
42: Idle Switch: is this the idle speed control (part of the fuel
system?)
51: Neutral Switch (MT): is this the neutral safety switch (part of the
electrical system?)

Could anyone list the appropriate part and possibly a website to find
the part for each of the codes?

The car is 4WD, 2-door, Legacy L. The car only has about 85K, but I
wasn't in very good shape when I got it a few years ago.

Greatly appreciate any help.

 

[Carl 1 Lucky Texan]

I just checked the Trouble Codes causing my Check Engine light to come
on (it's been coming on for years), and I had quite a few causes. I
was just wondering if anyone could describe the best way to fix each of
the problems (whether it's possible to fix myself or if I need to take
it in and whether the problem is even worth fixing since my car is
still currently running.)

The codes that I got ...

11: Crank Angle sensor
12: Starter Switch
21: Coolant Temp Sensor
22: Knock Sensor
23: Air Flow Meter
35: Canister Purge Solenoid
42: Idle Switch
51: Neutral Switch (manual transmission)

Parts I've found:
21: Coolant Temp Sensor: how hard is it to replace this?
22: Knock Sensor: doesn't seem too difficult
23: Air Flow Meter: expensive part ...is it worth replacing?

Questionable:
11: Crank Angle sensor: can't find this part
12: Starter Switch: do I need a whole new starter?
35: Canister Purge Solenoid: have only found 2 things close to this
(vapor canister and purge valve). What needs to be replaced or looked
at?
42: Idle Switch: is this the idle speed control (part of the fuel
system?)
51: Neutral Switch (MT): is this the neutral safety switch (part of the
electrical system?)

Could anyone list the appropriate part and possibly a website to find
the part for each of the codes?

The car is 4WD, 2-door, Legacy L. The car only has about 85K, but I
wasn't in very good shape when I got it a few years ago.

Greatly appreciate any help.

Have you cleared the codes to see which ones immediately come back? Have
you checked the alternator for output AND ripple? Have you checked for
corroded ground connections? 1 or 2 of those codes may be 'real' but it
seems unlikely to me to be all of them - not impossible of course. I'd
look for a bad ground and have the alt tested (with a scope) and clear
the codes and wait for a CEL and read the codes again.

Carl