The 93 - 02 F-body cars are real goofy about ground locations. Use a dmm and check for voltage drop. Just because it looks to be a great connection to the chassis, doesn't necessarily mean location is great. I've run into this with the same vehicles.
"Acoustics is the study of sound; a branch of physics dealing with sound. The law of physics is constantly challenge. Therefore in relation to acoustics; You must study constantly, for you will be constantly challenged." ...... Rainmanspl