About 4 year ago I put 70 mm , cold air with K&N, new 19# sample tube in maf meter, adujust fuel reg with gauge in engine compart. Also port match upper intake to new throttle bod. Under pullys. All this was done as one large(well to me any ways) project. When I ran car after all done it ran lean. BIG TIME lean . Uped fuel press, reduce timing back to factory. Ran good and idle fine. Now fast forward. About a month ago, as I was sitting at a stop light, car just drop idle to about 400 and bounce like crazy with engine at temp. I havent done any thing sine first round of above mentioned performance except for routine oil ,tires, flush radiator, You know! It happen all of a sudden with no repair involvred.