simple cross couple LC tank negative transconductance oscillator

I am designing a simple cross couple LC tank negative transconductance oscillator. but it doesn't work now. Here is my circuit description:
1. I have tunning the transistor size to make negative resistor equal -2/gm, and the load parrellel resistor is a little large than this value, so it should oscillate right?
2. I have tried different ways of start condition: set the cross couple output lines as 0 and 1, set them simultaneously as 1 or 0, put a pwl voltage source as supply with a little started pulse, put isource on each pair with a little start pulse.
But it still doesn't work, I mean no oscillate wave at the output when I ran the transient simulation. any idea with this guys?

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