The schroder valve on my friends 89 350 Z28 has a small leak. Would this in any way shoot a MAF trouble code? The code doesnt come on until I unplug the sensor. It gives the voltage high and voltage low codes, but runs fine. With the sensor plugged in it stalls very easy. If you put two fingers in front of the sensor it stalls. The valve is being replaced reguardless, just curious about the sensor problem really.

 

If the MAF is suspect,and will be replaced,replace the MAF relays the same time.With most 5.0-5.7 Bosch MAF cars,theres a power relay and burnoff relay.Sometimes you can try replacing them alone,cheaper,then see what happens,but usually if you tap the MAF and it stalls,its pretty much gone.
Is the MAF Delco or Bosch on the 89? Im just wondering..been a while since I played around with F cars.
The schraeder valve wont cause a code but can cause a fuel leak fire and should be fixed asap.