95 F150 5.0 running rough/erratically/smoking exhaust
 

It was running smooth up until about 2 months ago. I drove it across town and when I attempted to crank it to come home it wouldn't crank. It turned over very strong but wouldn't crank. I got a ride home and went back the next morning and it fired right up so I brought it home and just after I turned the engine off I attempted to crank it again and it just tuned over, but not fire/crank. I Tried it again late that evening and it cranked right up. It ran a little while and went dead and wouldn't crank. So now I haven't used it for several months but it will crank right up and run but when I turn it off it wont re-crank unless I wait several hours. Yesterday I cranked it up, it fired off instantly, ran a little rough at first, had blue/grey/white smoke from the tailpipe at first then tapered off and had no smoke for a time then some more with what I think is excessive moisture dripping out of the tailpipe (moisture maybe normal, not sure) and smells like stale/soured fuel when it's running. Anyone have any Idea what's happening? Thanks.

Hi Warren !
If possible, so we are all on the same page, when we go to start a vehicle we crank the starter /engine , while it is cranking it is turning over. When the engine begins to run on it's own we usually say it fired up.
Now can you see how confused I am.
Have you had to add any coolant to the cooling system?
When the exhaust stinks it may be because of stale fuel.
Have you had a chance to pull the vacuum line off the fuel pressure regulator?
There should be no gasoline in that line , if there is, the pressure regulator is defective.
Has anyone messed with the spark timing with the distributor?
Can you get your hands on a compression gauge and perform a compression test?
If I understand your post, the problem seems to be present when the engine has been run and is hot, does this sound right to you?

I'll try to keep the cranking, turning over and firing off straight. To answer your questions -
no one has added any coolant.
I'll locate and check the vacuum line for the fuel pressure regulator tomorrow.
No ones messed with the spark timing or distributor.
I seriously don't think I can get my hands on a compression gauge but I will give that some thought.
The engine doesn't have to be hot to act like I described. Yesterday, I cranked it up, moved it to the end of my driveway and turned it off. When I turned the key to crank it up again, it turned over very strongly but would not fire up. I wouldn't say that was a hot engine. A few hours later I tried it again and it fired right up no problem and I pulled it back to where it sits now.
Oh and just to mention, I'm not losing any fluids that I can see - oil, transmission fluid or coolant etc.. if that means anything.
Thanks.

Do you know how to check for spark coming from the coil? If so , when it won't fire up and start, remove that coil wire from the dist cap and place the end of it about 1/4 in from the metal part of the engine. Now when you crank the starter you should see a nice bright spark coming from that coil wire, do you?