Jeep Strokers

My new stroker...about 10K on the 92 rebuilt to a 96 stroked to ..4.7 normally gets 15 mpg pretty consistently. I recently put in a Spectrum..Hi flow- oiled type air filter similar to the K&N. It was a stock sized filter that fits into the stock Air box. My mileage almost instantly dropped to around 13-14 at best. My driving habits remained the same mostly highway with a little around town. I have a vacume gauge and the numbers appeared very similar. I probably went thru about 10 fillups all with the similar-reduced mileage...put a new stock type air filter back in and the next fillup was back to around 15 and it remains about that. Very disappointed..thought it would work the other way. I almost never exceed 3000 rpm so I can't believe I am leaning out the stock cleaner..causing better mileage. No appreciable power differences, but the mileage dropped almost instantly..no clue as to why...anyone else with similar issues?..Thanks

It could be an over oiled air filter. I run the paper stock ones, After I count what my time is worth it is the better choice.

Thanks...it was new from the box and *pre-oiled* by them...I will clean it and try again in the spring and see what happens. I don't race or run the engine past 3000 so I am probably not taxing the limits of the paper one ..just curious on why it sucked