fault codes and help please
 

i have a 93 wrx with sti engine just done a fault code test and tryed a reset and it come up with 11 crankshaft position sensor,23 mass air flow sensor,32 oxygen sensor,44 wastegate control solenoid valve...also will the ecu still reset or does the faults have to be fixed first,also

just some questions if anyone can help , when connecting the black and green connecters to do a reset i can hear the solenoid valve clicking away witch i thought told me it was working is this true,
also oxygen sensor is this the one on the manifold on the bottom left hand side as if you were looking down at the engine,

the car carrys on running if maf is disconected i take it thats had it,:brickwall
and the crankshaft position sensor is this the one under the alternater,

with the oxygen sensor is there a universal one i can buy,aslo with the maf as i know at the dealer can be expensive is there any were else i can get these from...:wonder:
one other thing could the maf and the oxygen sensor by whats causing my car to be over fueling..:wonder: cheers any help would be greatfull