Sooty plugs. 97 3.0 rebuild.inital start up long time to start .once idling a miss or something like that.pullef plugs sooty. No check engine light. Fuel bad? New pump good pressure?

 

Welcome to the forum

Well if you were cranking it for awhile then you could have a Rich start which would leave lots of carbon, the sooty stuff
Clean them, re-gap(0.044) and reinstall the plugs
Run it for awhile then recheck a few plugs

You can test for leaking fuel injector, all fuel injection computers have this, not a Ford thing
Turn key on
Press gas pedal down to the floor and hold it down all the way
Crank engine

It should NOT start, or even fire
The fuel injectors should be shut off, this is called Clear Flooded Engine mode
Key on, RPMs 0, Throttle sensor(TPS) at WOT(wide open throttle) = Clear Flooded Engine mode, shut off fuel injector pulses

If engine fires or starts then something is wrong
If you release gas pedal then computer will exit Clear Flooded Engine mode, or if engine fires and RPMs go above 400 then computer will exit Clear Flooded Engine mode

I use this every morning to start my high mile 4.0l engine, I want to pump oil thru the engine before I start it
So I crank it with gas pedal to the floor then release the pedal after 5 seconds