Cold start problems - 1993 90 V6

[David VS]

Seems that the colder it gets outside the harder it is to get my father's 90s started.  Any ideas?  With temps in the 30's (F) the motor will sputter and spit when turned over - sometimes even back-firing through the intake.  Only after serious flogging of the starter will it run and even then it's not running on all 6.  When the motor does finally warm up, it seems to run fine.

My father took it to the local Audi wrench and they plugged the car into their computer and cleared any codes.  They concluded that the motor was out of time.  Which I suppose is possible since I did change the water pump and timing belt last spring when rebuilding the motor (due to a seized water pump... and bent valves).  But I did use "the" tool for holding the cams and crank.  

Any ideas are greatly appreciated!

Dave - Grand Rapids, MI
90 90q20v
93 90s - cold blooded bugger