7.3 Ticks when ambient temp is below 35

[smoke_eater]

My problem is this, when its below 35 degrees outside i get a ticking sound like an exhaust leak from about 1600-2000 rpm. When it warms up outside to around 50 the ticking goes away and it runs quite like it should. I originally had a hard starting problem and the ticking sound so i checked my glow plugs and had 5 of 8 bad so i replaced all of them and the uvc harness's and the GPR. Also i have a new CPS thanks to the ford recall. Talking to a diesel mechanic today he told me to make sure the exhaust backpressure sensor tubing was clear and I ended up cleaning the sensor and putting a brand new tube on.. When i had the glow plugs checked the shop also did a buzz test on the injectors and found 3 injectors that sounded a little "muted" compared to the rest of them. I figured the UVC harness could cause this so i tried that first.. I don't know what else could be wrong beside's injectors, but want to make sure thats what it is before i drop a bunch of cash on something that doesn't fix the problem. Could it be my fuel heater and how would i check that? Thanks for all the help.

[cchase]

for some help...