BMW Repair: hard starting but not every time, o rings, cold start

Question
Hi Josh,
I have a 1990 325i, 5 speed, 200,000. I have replaced timing belt, water pump, cap , rotor, plugs, took off intake cleaned inside and out. Removed injecters and cleaned installed with new "o" rings and intake with new gaskets. I ohmed out plug wires seem to be with inlimits but the coil ohms out .5 ohmes first and 6300 ohms on second. When this all started was after doing all this it ran great but when after about three weeks it started to get harder and harder to start. I did notice that the throttle body had come lose. I retightened. Now sometimes it starts with in a few cranks and other times it takes few times to get it started. and when its running everything seems to be ok at ideal and cruz. Help Please!  

Answer
Mark,
 Looks like you've done your homework, a tune-up and all the works.  Have you checked fuel pressure?  The injectors might be working fine, but if they aren't getting any fuel to squirt that could be an issue.  The cold start on the car could be at fault as well.  Check the sensors on the thermostat housing (you already know how to check them with the Ohmmeter).

 Good luck,
 Josh