I recently bought a stage 1 transmission from fbodytrans.com out of Las Vegas along with a new Yank SS3800 stall converter. All has been fine until recently ! A check engine light came on which I had scanned reading"solenoid stuck in open position". The car drives fine, BUT ocassionaly from a dead stop the rpms will go all the way to 4krpms without moving then the car slowly moves .How do I fix this ?