Ground points on a 94 Chevy C1500

Trouble shooting an issues on my 94 Chevy C1500 PU. Cleaning all the grounds up on it. Grounds I have found, and cleaned.
Battery to engine block, 2 grounds to intake manifold, 2 grounds to back of passenger head (one to the firewall, the other to the frame), a ground to the ALDL port mounting bracket.
I have read that there may be a ground point near the PCM mounting location, but I have not been able to find one? Any other ground points that I may have missed?
Any help is greatly appreciated,
Thanks