Zhé

iTrader: (2)

so recently, after a oil change,
car was drivin fine untill i came to a stop light, when i clutched in to put into neutral, my rpm dropped down to 100 for a split sec then back up to 900. then the next stop light, itd probably only drop to 500 then back to 900.
this never happened before the oil change, car still drives as normal, but every time i go out for a drive, it has to do that once or twice, then never again.
i cant seem to figure out the problem, ppl told me it might be the vaccum hoses, i checked them, all still on and tight, since im full non seq, not many hoses to check.
had this happen to anyone else before? any suggestions?
any help is appreciated!