Following my trip to the mechanic for the intermittant stalling issue, the ABS light came on and they recommended replacing the two rear speed sensors. There was a considerable part and labor expense associated with the estimate to repair and in reading online, it seems to be that those sensors are typically replaced for such conditions but do not resolve the issue. The sensors themselves do not look complicated, but I have not found instructions on replacement. Are they hard to replace and/or in a difficult spot (the reason for the high labor estimate)? I've read where PnP switches, mass air meters and other components are more likely to be the real root cause. Could these be replaced (less expensively) as an interim step before attempting the speed sensors? TIA