hey guys I just sold my 91 slush box for a 93 lx it has 260k on the clock and runs good besides one issue, when i'm driving down the road and I push the clutch in to shift gears the rpms raise a little and stay high for awhile and then drop, instead of just dropping like its supposed to when you push the clutch in, can anyone tell me what this is? a throttle position sensor possibly? thanks for any help guys and girls