Nissan Repair: Timing, throttle position sensor, vacuum hoses

Question
-------------------------
Followup To
Question - Still a bit confused, with the tps disconnected I had a reading of 10BTDC the specs say 18 to 22 BTDC,the truck runs fine, do any vacuum hoses have to be disconnected for a true reading?
I have a 2001 Frontier 2.4L 4cyl please tell me the correct way to check the timing. According to the OEM Frontier service manual, it says to "disconnect the throttle position sensor harness connector", I did that and noticed that whether its connected or not I get the same reading, what is the correct way? Thanks, Rich
Answer -
Rich,

You did it correctly.  The reason that they say to disconnect it is that the idle will jump if you move the timing a lot.  With it disconnected the timing will move with just the mechanical timing.

Answer
Rich,

The base timing is set with the tps disconnected and it is that way since if you advance the timing too much the engine will rev up and if you retard it too much it will slow down.  With it disconnected the timing only works the mechanical timing.  No vacuum lines have to be disconnected.