i have a 1998 volkswagon jetta 2.0, 5 speed. i took the throttle body off and cleaned it because the previous owner never changed the air filter so there was a lot of oil inthe air line. i took everything a part and cleaned it. i installed a new throttle body gasket and cleaned everything. now the idle is really wierd it idles up and down. it goes up to 1200 and then it comes down to 800. the rpm justgoesup and down, up and down.it happens sometimes not all the time. i searched couldn't find anything. ANY IDEAS.

PCV valve??????
or that little sensor that connects from pcv valve to air tube??????