rajgohil

please help

Hi, guys i've got a problem with my Corrado G60, the car was run fine, but after i cleaned out my intake pipes and later starting it up the revs were unstable, what i mean is that the idles were jumping from 1000 to 2000. at its own will. I have not touched any thing. It also seems like its back firing in the inlet manifold. Has anyone got any suggestion? Any help will be greatful. Thanks in advance Raj.