About 1 week into the Titan with new E3D hot end. Had quite a few good prints, a few so .. so. Running PLA/PHA. Had a stringy print and adjusted the retraction a bit on Simplify3D and after one clean print.. it all changed ... Titan is now clicking and stops fully extruding 1 minute or so into a print. Have taken it apart numerous times, see nothing wrong. Tried increasing current on motor, no difference. Turned off retraction and same thing.. OK for a minute, then clicking starts and extruding becomes sporadic and job has to be stopped. AM frustrated and a hammer is beginning to look like an answer.. Any ideas would be welcome ..