Re: 1989 F150 4x4 EFI
You never mentioned this was a rebuilt before...What kind of engine are we talking about now? the original engine? 4.6L, 5.0L, etc?
Fonz is right, re-check the timing and while you are painting the engine do a compression test, sometimes rings break when they're fitted. Test for spark at each individual cylinder, if ok disconnect the injectors one at the time and see which cylinders make a difference. Sensor-wise, as far as I know, only the MAP sensor and camshaft pos. sensor will give you those symptoms you describe of blowing smoke all the time. cheers