Gremlins gremlins gremlins!

I would like to ask how can I tell if my sensor ground is going bad if it's shared between sensors? In my car from what I see on the schematics, the sensor ground is shared between TPS, IAT, EGR position, and ECT. If indeed is a sensor ground problem some of the readings must drift correct?

If you've got a sensor ground problem you're likely to see erratic readings on those sensors or potentially noise on the sensor inputs. A good test to start with would be to check the continuity between the 0V pin on each sensor and the sensor ground pin on the ECU. You may also see issues with the sensor readings if there is a power ground issue with the ECU.

The only fluctuations I have noticed are one on the TPS and another one on the tacho signal that sometimes pops to 7k or down to zero when steady state driving! To note the car has VR sensors on the Engine! I'm going to make the tests as soon as I have time!