My 94 Mazda 626 LX V6 has been having a problem where it suddenly quits while driving, usually after it warms up (10-15 miles) but more recently can happen anytime. Generally the engine RPMs suddenly drop to 0 on the tachometer and the car may continue to run with no warning lights for a few seconds but eventually the engine dies completely and the car stops. Occasionally can re-start by shifting to neutral while car is in motion then restarting, but usually not; car starts and runs fine after stopping, turning off, then re-starting but getting harder to re-start without letting it sit for a