I started my car for the frist time after rebuilding it 5 years ago it's running ok but the problem I'm having is with the tack. I step on the gas and it reves BUT.... The rpm is going in the opposite direction. If it idels for a second it will go up then back to 0 but as soon as I hit the gas it gets hesitant for a seond it revs but goes the other way. Ok has this happend to anyone else. Could it be electrical?