different between molded inductor and coil wound inductor???

i am doing a RF transmitter(using FM),and the circuit function well when i use hand wound coil inductor in the oscilating circuit(transmitter use LC oscillator).However ,whenever i try replacing it with a molded inductor,the oscilating circuit fail to work.
Hope someone can give me some explanation^^
thank you

I suspect that the moulded inductor is intended for EMC filtering purposes. and its "Q" ( ratio of resistance to reactance) is too low for the circuit to oscillate.