Hey Ambulator.
Code 33.34 are mass air flow sensor codes. You already know that.
33 means low voltage to the ecm from mass air flow sensor.
34 means high voltage to the ecm from the mass air flow sensor.
These voltage readings are either lower or higher then normal.
The code 44 is the electronic spark control. This sensor is operated by the knock sensor and when it feels knocking in the engine the esc will retard the spark on the distributor.
The esc will set code 43 when it senses an open or a short in the knock sensor circuit.
Possible causes for knock sensor sending wrong info.
Short or open in wire.
knock sensor wire is too close to a spark plug wire.
Warm the engine up and then while the vehhicle is on idle grab a hammer and kinda tap the area around the knock sensor and see if the engine retards or if it changes sound or feeel. If it does then that is a quik test to see if the sensor is working but it still does not mean that there is no short. grab a volt meter and a test light and grab ahold of a repair manual for this vehicle and locate the trouble codes. you will get step by step testing.
I would start by testing the esc first and then move onto the mass airflow sensor.
Hope this is what you where looking for.
Your next step is to now accept my answer. If you have any other questions then feel free to reply.
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I operate my own Auto repair Shop
ASE certified all cars and Automotive business owner.