Got a 2002 4.7L that is having problems starting....it cranks and cranks and cranks and after a bit starts. When it does start it sputters a little and smoke comes out my exhaust blue in color (almost like unburnt gas). I have tried a new fuel pump...new spark plugs...new coil packs. I have an idea it might be an EGR valve. Any ideas or the location of this valve. On most vehicles I have seen it right on top of the engine and easy to get to. I took it to the dealership and they keep telling me its a gas cap...I already replaced that too. If it has been sitting a while or sitting out in the cold for a while it fires right up.

 

crank positon sensor maybe?

 

Im thinking the crank snesor also.

 

I replaced that this past summer also thinking this would solve the problem...had troubles finding it but found it on the front of the engine...I am at a complete loss of ideas...found out the truck doesnt have an EGR or a mass air flow sensor...

 

I have a 3.9 that won't start after sitting for a while. If it's been running it will start right up. I replaced plugs, wires, distributo cap and coil, engine temp senssor, ignition coil, radiator, upper hose assembly. The dealer told me it was a vacuum leak and needed to replace the intake gaskets an plennum pan gasket. I did that and it still wouldn't start. I could try to start it and it would just crank and crank and crank until it either started or the battery died, then I would get out the jumper cables and keep trying til it started. Because once it started it would rough idle for a few seconds then smooth out and I could restart it if I turned it off.
Another mechanic said he noticed antifreeze in one of the cylinders and determined that I need a new head gasket. I am in the process of deciding wether to do it myself or have someone else do it. Or just swap out the engine completely.
Hope this gives you some help, I am still at a loss.