Purge valve cycling between 125-120 psi every few seconds

I'd bypass until you get the dryer replaced. Bad spitter valve on dryer. The cold weather made it worse. You might have other air leaks too. Just bypass the som beach so your truck stop neighbors can get some shut eye.

 

Replace the purge valve and replace the cartridge in the dryer. Should be done every fall anyway. The dryer that is.

 

Dryers are cheap, just replace with a reman and swap for the core.

 

leaking unloader valves in the compressor will do it also ..

 

I would replace the entire dryer.

 

It could be worse, I had a Peterbilt here that would fart for five minutes after shutdown. Literally it sounded like someone easing out a bunch of squeakers, replaced the purge valve and all was good.
When was the last time you changed the desiccant canister?

 

LOL, gotta love the simple solutions. Reminds me of the guy that rebuild his motor then realized he forgot to put fuel in it.