The audio cuts in and out intermittently

- could be old tech
- weak battery
- does it have antenna? - that's old!

The volume control on modern units is done by a chip inside the unit. That determines the volume and sometimes things like the tone. The fact that it is intermittent, probably means it suffers from a heat problem. The only cure will be a new chip. If you can do this yourself then just follow the volume control wires back to the main board.
If you can't it's off to the repair shop with it.

Radio switching to weatherband is an indication that the weather alert function of the CB is turned on. If the weather channel transmits an alert signal, it will switch to weatherband. Speakers cutting out may be your VOX setting is too sensitive or the squelch setting on the CB is too sensitive. Lower both the VOX and squealch and see if that works. If the issue continues, contact Iron Cross Audio for more help. www.ironcrossaudio.com

It IS an airborne signal so you can expect it to be affected by the antenna and other electromagnetic interference. Most FM tuners have a selector for how aggressively they accept or reject a marginal signal. Perhaps yours is crossing that threshold periodically.

Air intake not adjusting correctly or is there a manual cold weather lever on the air intake pipes on these?
lamda sensors on exhaust? you might get an answer from the ecu if you plug it into a diagnostic machine. I'd take it to a garage

Sounds like your SNR is getting too high and causing the signal to overload. A few things can cause this a bad splitter that causes the signal to bleed and introduces noise, or a more common issue is having a weak signal coming from the cable provider and once it goes through a splitter it causes the signal to become to weak to be stable.

Since it sounds like your cable has been working up until recently, you may have had a cable or splitter go bad.

Call comcast and have a technician come out and test the line.

Digital is much more sensitive to "noise" and cuts out if signal is not strong. Contact your cable company to have them check the signal level you are receiving.

If you are indoors then move outdoors to get a signal.

If you are outdoors then move your location by a few yards and sometimes it will suddenly aquire the satellites.

Happens occasionally with my unit. I normally set a route up then start driving and it suddenly starts to work OK.
HTH
Peter

have you tried to move the switch to channel 4 on the back of the vcr ( you will have to watch the vcr on channel 4)

Sometimes an amplifier's preamp can't handle certain signals/frequencies at a high gain, so they cut out. Bass guitars are especially prone to giving such a strong signal.
I bought an older, nonworking bass amp recently and fixed it just to find it had the same problem. Best solution is to put a low ohm resistor at the amps input, but if you turn your guitar down to half volume it'll have the same effect: should prevent it from cutting out.