That's a problem I have seen many times, Sometimes I have even solved it
. The first thing i would do is to look at all the connectors both antenna and dc. first on the CB . since it used to be fine it is likely something simple like a dirty/corroded connector. Next I would try to determine where the static is entering the CB. Is it coming through the antenna or DC. Disconnect the cb antenna, key up the 2m radio, if it goes away then you have a starting point. Try a different antena on the cb a mag mount would be good.
I have assumed you have adjusted the squelch on the cb.
and checked VSWR.
Try a different antenna on the 2m, again a magnetic mount helps.
Do you have an external speaker on the CB, try unplugging it.
Borrow a friends cb and try it in your jeep..
Have a friend park his jeep next to yours, see if his or hers, recieves the interference.
Does it make a difference what channel either the cb or the 2M is on.
Do you have a portable, you could tune to the same freq as the mobile,
Can you change the out put power on the 2M Hi/Lo setting?
It just goes on and on sometimes.
Do you know anyone that would come over and help you, (I think you do