Check back on all the spots vacuum leaks can occur--you know them as well as I. Back behind the intake and of course the Disa valve--I make my own gasket to fit between it and the intake just to make sure there's no problem there. As your stating your watching the mileage decrease--where you live can also be a factor in this--it's getting cold again and as it gets colder , it's taking more time for the engine to heat up to were it needs to be for effiency. Check those fuel perimeters athat might give you a start--I recently change out my oil temp sensor and helped my car with extra mileage--but there was a code thrown in that instance--might take some electrical cleaner and clean all of the hot plugs that is associated with the fuel delivery--I changed out my per 02 sensors back over a month ago and used the Denso brand this time--my average fuel useage went from 23.7 to 25.8--on the highway it's at 31 to 32--I would also suggest that you take the car out for a long drive from time to time just to blow the soot out of it--and cheak what kind of mileage your getting out on say 100 mile drive--it's falll get out and see some country--lets hear back on what you find
Last edited by poolman; 10-14-2012 at 06:34 AM.