Audi A4

I have a 98 Audi A4 1.8T, manual, with ~160K miles.
I have been experiencing idle issues. When coming to a stop and I depress clutch, my RPM's drop to about 450 then return to about 900.

Also when stopped and idling, my RPM's will slowly rise from ~900 to about 1500 RPM without touching the gas pedel.

I have installed a K& N panel filter, would the oil from the filer be getting on the MAF sensor and causing idle problems?
I have checked/changed all of my vacumm lines, coil packs, plugs, ignition module etc.

Any suggestions would be appreciated.

June 20, 2007.

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