Toyota Repair: four runner 1994 3.o ltr v6, check fuse, mass sensor

Question
i purchased a four runner with a fault as follows--
when you inially try to start vehicle it will run for approx 5 secs & stop.
compression apeared in the water jacket so removed and replaced both heads ( faces soft )
built back up replacing the knock sensor and wire
vehicle still only runs for approx 5 secs
checked air mass sensor ( door operation ) all seems ok
help thanks ian

Answer
Did you do the torque pass correctly on the heads?
How was the compression test afterwards?
Check fuel pressure on fuel rail; place ignition switch to ON to see if pressure builds up.  If pressure does not build up - fuel pump problem (check fuse / relay, fuel filter clogged, etc)  If it does, take switch to START and see if pressure drops off significantly.  If it drops you have a problem with fuel delivery (fuel pump suction clogged, fuel pump failing, plugged fuel line)

Hope this helps,
Vince