I purchased a 2000 Chevy two months ago dually with only 118000 on it from a work associate that he said the dealer said it needed a lift pump on it. What the truck is doing is it will start up and when you are driving the truck will just cut off at any time (idle, running, towing, etc) the truck would act like I turned the key off. When it would turn off it would not shutter like it was out of gas which you would think it it was a lift pump problem. After a couple of weeks of this I took it to the local chevy dealer. They installed a new lift pump for $875 got truck back and it still keep cutting off when ever it wanted to. Took truck back to dealer who said that I needed a Throttle Position Sensor which they installed for $190 got truck back and it still keep cutting off while running whenever it wants too. Took truck back to dealer who now says that I need a new injector pump. Dealer installed new injector pump for $3478 got truck back and it still keep cutting off while running when ever it wants to. Took truck back to dealer who then said that the truck now needs new injectors (they said that it needs all eight injectors) the dealer installed all new injectors and new fuel filter for the price of $1846. Guess what truck still cuts off while running whenever it wants too. Dealer towed truck back to shop where they installed another new Throttle Position Sensor (dealer said the other one must of have been bad) truck still cuts off. I explained that it seems to me that when I would hit a bump in the road is when it seems that's when the truck would cut off. I asked the dealer is there anything in the engine compartment that could be loose to cause the motor to just shut off while running. I was told no the only thing electrical that would make the engine cut off would be the iginition switch. Please help I am now broke. What direction can I go now. I have no codes or check engine light that has ever come on to hook a code reader to help diagnose the engine problem. It is a nice great running truck when running.