2H the temp light gauge flickering, engine not running smooth.

Hi!
I have the following problem:
When I start my car (Cold) immediately the light of the temp gauge is flickering.
The car runs like its not getting enough fuel.
This stays for 10 - 20 - 30 miles…no different.
But when I stop the engine, and after a while start it again ==>
The car is running much better and the light is out !
What could this be ?!?

The needle works…
Disconnecting the lambdaSonde ==> no difference

Thanks

Frits 

sounds liek a bad earth to me, make sure all the earths on the engine are clean and the main battery earth is good