If you think you have a grounding issue. How would you go about starting to check for that. I having some strange odd issues. Like the car starts to run rich out of no where. Then if you come to a stop it is so rich it will die if you let it die and then start it again is not rich anymore. After that the drivers side brake light and blinker is not working. If you then turn the car fully off and the start it again or just turn it to accs on the blinker and brake light works. Also no matter what you do the STFT is always lean. Also getting codes for like the heat exchanger pump no working but it is working. So just some random issues. So I am thinking I might have a ground that is not good or lose. Short of going through everyone and checking it. I was wondering if someone knew of a way to check.

Thanks