MAXXspeed18

While me and my friend were installing my reverse gauges, we accidently laid the gauge face down...well we went on to install the gauges and connected them and all of a sudden my gauges didn't work the same no more....the The Tach idles at like 1300 which is suppose to be just under 1000 RPM, i don't think the needle is sticking to anything cuz the indiglo gagues are put on and lined up and everything....also, when i turnt he car off, the needles drop at zero instantly, so its not like theres a uneven spot on the gauge surface thats holding the needles from moving smoothly....also, my speedo is acting funny i think also, when i'm driving and i'm slwoing down, it doens't seem like the needle is slowing down fast ennough and reading my proper speed....for example...i could be slowing down from 50 MPH and be going 35MPH but the needle i think takes a lil time to catch up and it'll say i'm doing 40 or 45 MPH, is there a way i can fix this? i know for a fact that the gauges are lined up perfectly and everthing...some help me out