Possible fuel issues

My vehicle runs when it wants to. The engine and transmission were both rebuilt about eighteen months ago, just before we bought it from the original owners just due to the high miles. We have not had any problems with it until the last few months (bought it February of 2015). We had to replace the fuel pump in February after the truck died going down the road. Replaced again in April after it died again going down the road. Again, in May. We have checked the relay and it is fine. The theft light does not stay on. Fuel filter is new. Only code that is thrown is the P0446 for the evaporator system, but we have never had any problems filling up. Hubby thinks it is either the crank position sensor, the cam shaft sensor, or both. I am worried it is the computer going bad. Any help is appreciated. Also, when it acts up there is no fuel getting to the engine but there is still fire at the plugs. We did discover on the last pump change that the ground was bad so it is now grounded.