what did i do?

[KaRMa]

well, my truck has been running horrible (no power, white smoke, rough idle, stalling) so ive been working on it. ive changed the fuel filter, oil, air filter, pcv valve, vacuum hoses, and thats about it. it still has been running this way until today, when i went out to start it and it wouldnt go on its own. its turning over, and sounds like its trying to start, but it doesnt. any ideas?

[Stuka]

if your getting white smoke that makes me think coolant leak. Either int he intake of head gasket. I would pull the plugs and turn the engine over with someboddy watching to see any water squirts out of any of the cylinders.

If not, I would do a compression test while your at it. As that white smoke may be a light blue, which would mean burning oil.

Then since your there, if that stuff checks out ok, do a full tune up. Plugs, wires, cap, and rotor. Then see how it runs.

[KaRMa]

i pulled the plugs and they look fine, my friend did a compression test, but i really dont know how to interpret it correctly... he told me it was not too bad, but not good either.
it was: 125,135,125,135,150,135,140,150
the PO bought new wires just before i bought it, ive lookd them over, still like new. the cap and rotor look fine by visual inspection

[Lugnut]

A possibility is the vacuum modulator on the auto. trans. is leaking and the trans. fluid is being sucked into the engine, thus a cloud of whitish smoke from the exhaust.
Can't really say that this would cause the starting/running problems you're having, but it's possible.

[J4GRAND]

No vacuum modulator on a 727 if he is referring to the rig in his signature.