Re: I C Pump
That lurch is the supercharger clutch disengaging. The HP that was being used to spin the supercharger is now used for forward propulsion, for a half second anyway. Your intercooler pump is almost certainly shot. Go ahead and replace it. Even if by the very remote chance the pump is not the problem, the pump will eventually fail anyway so there is nothing to lose by replacing it now. I'd go for the Johnson pump since it has a longer life expectancy than the current one. This will offset the the higher cost of the Johnson.