long story short it is a 99 GTP bone stock except k&n filter. I am unsure on the tune up items we are slowly getting to that. it was bought a month ago and she needs it for mostly a highway car then a little fun on the weekend but the big thing is she has constant KR and it worries me. there is 106k on it, is there anything that could just age related causing the KR . also I am going to dremel out the front manifold and slap it on there and gut the air box. I will do the fuel filter and see if that helps but is there other ideas that I can use as well as advice on a mileage tune. she uses this car as a commuter car over 100 miles a day. any insight would be great