This one has me stumped. The truck is a 2000 Silverado 1500 Ext. Cab/ Meduim bed RWD with the Vortec 5.3L v8. You put the key in, it starts (or at least it did) but does not anymore, and runs for 2-7 seconds and then the engine cuts off. Mileage: 250,000 When the engine does run for a few seconds, the RPM's hover at around 500, and then they go to zero and then the truck is dead again. I have checked: The Mass air flow sensor and cleaned it (CRC Mass Air Flow Cleaner) - Did not resolve the issue Changing the o2 sensors (3 of them) The check engine light comes on sometimes (it is not on now) for a lean bank 1; which I replaced all the spark plugs whith delco plugs in July (last year) and put new wires on it. The problem is more noticeable with the the colder it gets Fuel filter was also replaced 6 months ago. I am not sure what more to check.