Micromitter- Low TP! symptom
The low value of volts at TP1 indicates that the closed loop frequency control is not operating. I'll bet that most builders having this trouble are trying to use the 88MHz end, and that makes sense because most would think that is a quiet part of the band. (I have a friend who bulids FM transmitters in the 10kW range for community radio, and he suggest that in Australia, this part of the band is less suitable because it is used for low power intentional transmitters)
I had 0.6 volts at TP1, so I tried running at 107.9 MHz and the voltage at TP1 suddenly jumped to about 4 volts. I could then easily trim to the 2 volt spec. I chose to run at 106.9 MHz which is silent in Melbourne Australia. It looks to me like the range of adjustment of L1 is not enough to cover both ends of the band, and if you need to use the low end of the band, L1 may need another turn. I can't say whether that won't then have a too high value though, you will need to experiment. The 22 pf cap could be increased a little for the 88MHz end, but this will have the effect of reducing the range over which the varactor diode operates, and reduce its freq range. I am using a 6v battery too, so I set the volts at TP1 at 2.5 volts using the slug adjust.
In short, if you have 0.6 volts at TP1, it does not mean there is a problem, try the 107MHz end.