I did research on the Gen V swap prior to doing it as far as what was needed to accomplish it. The day before i did it, i was told that i'll need a tune afterwards. i needed to tune my car anyways, as the only one i have is a ZZP pcm. but OMG, my gas mileage has dropped so bad since i did the swap. Im not the type to sit home long, so i'm always out, and it's like i'm at the gas station every 2-3 days ($25 a time). IDK if its because of the swap or not, but thats the only mod i've done recently. I have no vacuum leaks...only a slight coolant leak at the adaptor plate. Does anyone have any idea if the untuned swap is the culprit? Should i put my Gen 3 back on until i can get a tune?