[rd400rz]

I was changing my maf sensor today 2ND one first one was replaced at about 80 k car now has 88 k on it also car has a k&N in it i I was getting a PO102 code now that's gone car is running good ,I noticed a fair amount of oil dirt on top or by the motor intake tubes ,my car is a 98 and never had the aos replaced ,I noticed a sucking air sound kinda like a four barrel carb on a old muscle car would sound like vacuum leak ?when I gave it gas with the engine cover off ,also the idle with fluctuate a bit when I turn the air on it will go down a bit ,I have only had it smoke on start up a few times since I owned it I have had it for three years ,no other problems should i replace the aos ,could that have caused the maf to fail in 8000 miles ???