a few things I might try since I now believe in bonding, bonding and more bonding.
try to bond the gas tank better and alternator. Upgrade the bond strap from the frame to the engine nt replacing it bit adding one.. I could see thru the one on my Jeep as is very thin, not really made for HF.
Also is the ferrite your using a mix 31? my understanding is the mix 31 is for the HF freq we use. I would put at the antenna.
I do have a few of these on my coax. Not sure if they are needed anymore since I bonded things better...
someone else had this issue recently and they were making a choke and going to install it very close to the gas tank... not sure what ever happen to that setup.

I got a good RG8 coax and not the RG58... better shielding..

 

I believe you are talking about the choke I built. I haven't installed it as of yet. The hours I've been working and my rig being my DD haven't allowed me to do the install. I will post a separate write up in this section when I finally get to it.
I am not holding my breath that it will solve it. Until then I'll just keep bonding, bonding and bonding.

 

Today I powered up my 2 meter HT n the jeep. It has a cigarette power source. I noticed it has a RF/EMI filter on the power cord.
I've seen these around. maybe it will help you or anyone picking up noise from their Jeep.

Don't know if it will work, just a suggestion. The filter is there obviously for a reason

If you go to Mouser Electronics website and look up item # ZCAT1730-0730A-BK you see what it looks like on the inside and other technical specs.
I would get 2 of these filters and put one on the positive and one on the negative leads.
If anyone tries this (or has tried it) let me know.