Cobra 29LX drops out after peak and tune!

I had my NEW Cobra 29lx peaked and tuned buy a very reputable shop. Now after the P&T the CB cuts out, like it losses power. I'm in a Volvo that has the power studs for the CB. I thought maybe the studs were the problem, I stripped the power and ground wires back further and wrapped them around the studs and really tightened down the nuts on the studs. Didnt work! So I then bought a power cord that that plugs into the 12v outlet and that didn't work either. The CB shop reopened the CB and said everything checks out fine. Whe in the CB shop the CB didn't drop out once. So I went on my way. The next day I was able to stop at another shop where the CB was opened up and the tech didn't find anything wrong. Once again when the CB was in the shop it didn't drop out at all. I borrowed a used radio from the 2nd shop and hooked it up with my both types of power cords I had and that radio didn't drop out once. So my question is why would my CB start to drop
out after a P&T? It didn't drop out once before the P/T even with my SWRs above 2.0 and the antenna warning coming on?

 

It drops out anytime. Recieving, transmitting, or just when it on. SWR are even across all channels 1.2. When it drops out all the info on the screen goes blank but the screen stays back lite. Almost like when you first hook up to power the screen goes on then clicks and goes off. Sometimes even with the radio turned off but still plugged in it will click and power on then off. I'm puzzled, because the cb and 12v outlet are always powered.. The radio does it on. Oth circuits.