i dont know if this will help but it has worked for me on my vehicles for years,,,,, i had the same problem static poping coming in radio touching antenna would get slight zap even sliding in and out of seat and touching door handle would get ya...... first thing is make sure radio is grounded, amp is grounded and antenna is grounded,,,, one way to make sure of this is unhook antenna from radio and it still powers up,, same thing with your amp if you unhook coax in and coax out and it still lights up then it is grounded, next is the antenna with a ohm meter check the coax shield on the radio end to ground and make sure it is not showing short,, the thing i do is have 2 rubber grounding straps from frame to the earth ground,,, that means i have 2 rubber straps that drag on the road as i drive along.... much like truckers used to do years ago to stop static buildup on loads,,,, just a few thoughts hope some help here 73s midnight special
you would not believe how many radio squealings and amp problems come from just radio not grounded right or amp not grounded,,,, what is happening is the ground that is for radio is not coming from ground wire on radio but thru the coax shield,,, some people call this ground looping.