I have a 2005 Ram 3500 with a 5.9 Cummins. I drove it home one day and it would crank but not fire the next. The lift pump works, but it acted like it was not getting any fuel. I took it to a reputable shop and they said the engine is getting fuel, but there is no compression on one of the pistons. Is it possible for it to start one day and then not the next due to a compression issue like this? I have tractors that will run with a dead cylinder with no problem so shouldn't this as well? Is there anything else I can look at that may be causing the issue? They suggested replacing the engine (Long Block for $13K) , but the truck is only worth about 12-14 running, so it's not really cost effective to do that.