Originally Posted by turnofftheradio
if it is efi you will throw a MIL and you gas mileage will go down.
If you can't tell if its efi or not, look for an o2 sensor.
I thought this was only true if you have an o2 sensor post cat. A lot of early OBD only has a O2 sensor pre cat, so the PCM really isn't monitoring the effectiveness of your cat.
Scooter can correct me if I am wrong