Help with antenna on Volvo..

I have an odd one I can't seem to pin down. I have the standard 2 cheap whip set up on this Volvo, in the stock locations. I'm using a Cobra 29LX. The gauge on the radio shows my SWRs to be less then 1 on channel 20. But after a few key mics the screen flashes antenna warning. I'm not sure if I'm evening broadcasting anything I say when I key the mic. I am recieving transmissions from other drivers. I'm thinking about going with like a Wilson 2000 on the driver mirror, but the Volvos don't use the standard 3/8 mount. The coxal has I believe M6X1.0 stud on it. Not sure but I know a 1/4 fine thread is not the same, forgive me since I'm on the road and don't have a thread gauge with me. I did take my mirror driver side mirror apart because I couldn't find the stud when I got the truck, I found the coxal cable had fell from the bracket because there was nothing to hold it to the bracket only the whip. I had to make a road repair so I just got a grade 8 5/16 nut and used it as a spacer then thightened down the whip. Worked for a little while now I get the same antenna warning. So my questions are. Does it sound like a bad antenna,Do I have to run 2 antenna, Will the Wilson 2000 be ok with an out the box 29lx, and would it mount on this Volvo?

 

RR thanks but I don't think that's going to work. That metric stud come right out of the coxal cable on this truck. It's not a femal coxal cable to thread on to the bottom of the center stud assy. Any other ideas?

 

09 670. The driver side wash missing the rubber washer. Road side repair was done on 3/25 worked for a little while. I took that plastic washer and nut from a stud kit and installed it on the stock coxal. It did not help. So then bought a Wilson 1000. Installed on driver side with plastic washer and removed the passenger side antenna. Still got SWR pegged on radio meter. Put the tip of the Wilson all the way in and still high on SWR. So I put the 1 Wilson on the passenger side with tip all the way down and now my SWRs are CH1 less then 1, CH 20 2.2, CH 40 2.2. No more antenna warnings, and I got a copy on a radio check. I don't have a antenna on the driver side now. Are SWR still to high, and is running a single on the passenger side okay?
Thnx

 

I would rather have an antenna on the driver side, but it just does not work out that way, anything I can use to replace that rubber insulator, to get the antenna on the driver side?

 

Antenna warning came back. SWRs on ch20 and ch40 are now up to 2.6, and I don't think im transmitting anymore. The funny thing is I don't get the warning on ch1.