On a stock vehicle, this works pretty well. Everything is close to factory. On a modified vehicle, the Volumetric Efficiencies are all over the place, and on a Speed Density vehicle with no O2 sensor, the computer is totally blind. It works solely off of RPM, temperature and the default tables.lets say you unplug the o2 sensor, does the computer still use a base map to keep everything running?
No kidding! When the light came on Tuesday morning, I kind of stared at it dumbly for a moment, and thought, "Well, if it's there later, I guess I'll pull the flash codes..." In my car, I would've plugged in the Bluetooth OBD2 module, fired up Torque on my phone, and known exactly what the problem was. While sitting at a stoplight.I get codes for my O2 sensor and PIP sensor all the time. No driveability issues at all, just the CEL and it usually goes off a few miles later. People have been spoiled by OBDII and don't remember how bad OBDI engine management systems are.