Good evening,
For almost 3 years I have a stock Tevo Tarantula,except for some minor improvements.

Some months ago while printing a 4 hour PETG print my nozzle clogged for the first time ever.
I unclogged it and from that moment till now the nozzle cloggs and I can't get a print finished.
Sometimes it happens at the start,sometimes after 1 hour.
It doesn't always totally clog, but when it does you can hear the extruder clicking and underextrument will appear or it wont print at all.
So what I did:
-Tried another extruder (I have a Titan extruder,tried the stock one)
-Changed nozzles
-Changed PTFE tube
-Changed throat,even got an all metal one
-Changed the fan with a bigger 40mm one,in order to have more airfow
-Updated the firmware,from Marlin 1.1 to 2.0.
-Tried other filaments.Neither PETG,nor PLA can print.
-Even applied thermal paste to the throat and insulated the hotend
-Replaced the hotend block
-Replaced the thermistor and the heating element

I can't find the cause of the clogs and I've replaced everything that the filament goes through.It just doesn't make sense.
I am using Simplify3D and even when just asking the printer to extrude ,the extruder will start clicking.

So any idea what else I can check on,before I get a new one and just throw this one out of the windows?
Thanks.