93' Olds 88 bad ground?

This 88 has a 3800, just started intermittantly running rough, and now I backed it partway down my driveway and when I went to put it back in the garage, everything looked normal until I turned the key to start it. The interior lights got dim and the ignition is just clicking as if the battery was dead. It's not, I hooked up some jumper cables to my truck, but the lights are still dim and flickering. Could I have a bad ground?
Any help would really be appreciated.

pull your batt cables and clean them

Tried it, no help. I get a solid 12.5 volts measured between the pos. battery post and the block.

check the battery cable ends (pull on them )they sometimes currode from the inside

Also check down by the starter some times the bolt get's a little loose and lose the + side .... And it might also be the contactor in the solonoid or the copper bolt .. some times they get pitted and burned .....

Thanks for the replies, It was the Positive battery cables, it has two cables, connector plates and a long side terminal bolt. The plates were severely corroded, I cleaned them (no really this time) and now it runs like a champ again. Michelq - you were right!

Thanks for the replies, It was the Positive battery cables, it has two cables, connector plates and a long side terminal bolt. The plates were severely corroded, I cleaned them (no really this time) and now it runs like a champ again. Michelq - you were right!
thank you for posting the fix