First thing, NEVER key up your mic with out an ant on there, you are going to fry your radio if you do, second, NEVER key that baby up with out it being grounded right. Your radio and your ant have to be grounded or you wont talk or listen.
If you havent already done great damage to the radio take it down to a CB shop / Truck Stop wherever the "old timer" Cb guys are and have them tune the SWRs on that thing. Also ga ahead and buy new coax for it, coax is your friend and you dont want to get bad coax like having a bad friend. Try making a mount on your spare tire rack, use some old shelving angle iron, like the kind that has the oblong holes in it to adjust the shelves, Your going to need to take the rack off and make sure there isnt anything shorting it out either. Grounding is the #1 thing always screwed up on a bad CB. And dont worry about getting a really expensive CB just get a GOOD antenna, its worth every penny to get an awsome antenna. CB's only can transmit so much power and they are all almost the same from factory and to be honest you dont need power to talk to your buddy thats 100 yards behind you on a trail.
Go
HERE