What do I need to do if code 27 shows on meter?

That is normal there is a dile on the dash that controls the timer on that.

Need to have a meter to check continuity between new alternator and the new battery. Make sure all connections are tight. May have open fusible link which a meter will reveal. May have bad voltage regulator in the ECM which should show a code. I do not like relying on dash gauge, they can be inaccuate. Time to have a mechanic check for codes and continuity.

Clearing the codes is simple that is done by removing the fuse of the EFI from junction box 2 for 10 seconds. Make sure to remove the jumper wire and switch the key off before clearing the codes.

Here are some common Lexus vehicles 1990-1995 codes:

Code 12 and Code 13 Rpm signal circuit fault
Code 14 Igniter signal circuit fault
Code 16 ECT control signal fault
Code 21 and Code 28 Main oxygen sensor fault (for ES300; SC300 & GS300 models)
Code 22 Coolant temperature circuit fault
Code 24 Intake temperature sensor circuit fault
Code 25 and Code 26 Air fuel ratio fault (for ES300 & SC300 models)
Code 27 Sub-oxygen sensor circuit fault (for ES300 CA & GS300 models)
Code 31 Low airflow meter voltage (for ES300 and GS300 models)
Code 32 High airflow meter voltage (for ES300 model)
Code 35 Barometric pressure sensor circuit fault (for GS300 & SC300 models)
Code 41 and Code 47 Throttle position sensor circuit fault
Code 42 Vehicle speed sensor circuit fault
Code 43 Starter signal
Code 51 Switch condition signal fault (for ES300; GS300 & SC300 models)
Code 52 Code 52 and Code 55 Knock sensor circuit fault
Code 71 EGR system circuit fault (for ES300; GS300 & SC300 models)
Code 78 Fuel pump control circuit fault (for GS300 & SC300 models)

newton meter [N*m]:inch-pound [in*lbf] Bookmark newton meter to inch-pound Conversion Calculator - you will probably need it in the future.

24 Intake air temp sensor and 32 mass air flow meter circuit or vacuum switch failure . Air temp sensor is internal in the vane style mass air flow meter it is not replaceable you will need a new meter.

Code 12 is more or less common, code 27 is a problem with the injector or the circuit.
You may need to research the code 27 to get the testing procedure and the wiring diagram. Usually the reason for the code is too much resistance in the circuit or an open circuit. The computer grounds the injector to make it open.

Speed Sensor has nothing to do with the engine cutting off
PO322 is a Generic Code for a Knock Sensor
You need to Google your codes & read up
An OHM Meter won't do anything for you on a Speed
Sensor,need a scan tool or scope
I would say you have an overheating condition to correct
& the knock sensor plays a role, wouldn't you think!

Depends. You would need a volt-ohm meter and the book to get the testing steps. You may need a scanner too.
You would need to be able to test the circuits in the ignition control module where the coils are mounted and the crank - cam sensors.

The points should be set with a dwell meter to 27 degrees. Without a dwell meter you could use a feeler gauge and set them at 20 thousandths of an inch. You'll also have to reset the timing because point dwell changes the timing.

I'll try and help with a few of your codes, code 12, will show if the diagnostic term is grounded to access codes, it will show any time that is done and the engine not running, all other codes will show after. The 26, 27 codes have to do with the engine over heating or a coolant sensor. #44 has to do with you Ox sensor, indicates a lean running condition. Pos. due to engine running hot. .