Kmartsoup

Known symptoms:
80psi fuel press before car is started
Holds 80psi while erratic idle
Drops to 0psi ~10-15sec on shutdown
Air/fuel ratio at 10:1
Ignition timing normal

Things changed/cleaned
Changed spark plugs
Changed injectors
Changed fuel pump
Changed fuel filter
Changed o2 sensors
Changed intake manifold gasket
Cleaned maf sensor
Cleaned throttle body
Cleaned electrical connections

Things verified
Verified fuel press sensor ok
Verified spark plug wires ok
Verified coil pack ok
Verified proper/clean fuel

Possible thoughts:
Computer failure
Maybe vacuum issue

Any help is more than appreciated!

BabyGT

How did you verify the coil pack? A bad pack can test find on a multimeter. How did you verify the plug wires as well. They might have the proper resistance from one end to the other but if the rubber coating is breaking down at all there is a chance for them to arc to anything close. Had a thunderbird that they tested fine with a meter but two of them were still arcing on each other, changed them boom, car ran like new money. I bought that car for 400, replaced plug wires and flipped it for 1200.

Kmartsoup

Checked for spark on the engine side. Thought the spark wasnt getting to the engine but just did a screwdriver in the plug type of test. Ive had the coil box replaced as well as the wires.

PNYXPRESS

fuel pressure looks fine to me, not high.
erractlc idle is due to the throttle body or IAC gummed up or clogged.


How does it run/drive when under a load?

BabyGT

That's not a good enough test for spark, just confirms that its getting A spark, could still be a weak spark. Might still be wires. But check what PNY suggested, the iac being out of wack even a hair can cause noticeable problems.

Kmartsoup

Fuel pressure shouldn't be that high. It is supposed to be 35-60psi. I personally only see it running 40psi anytime prior to this. Car "misfires" through the entire rpm range, wouldn't produce power, and is shooting black smoke out of both tailpipes.

PNYXPRESS

Then a sensor is unplugged somewhere and the car is trying to prevent a lean condition and is pumping too much fuel. Check the MAF connector and the intake tube for cracks or holes.

Kmartsoup

Checked every connector, cleaned them out too just to make sure. New symptom though, my aeroforce gauge isnt reading batt voltage. I ordered a new ecm and its free due to warantee but i have a bad feeling its messing up and not functioning properly. It could explain the rich fuel mix but still baffled a out the 80-0 drop after shutdown.

PNYXPRESS

Wouldn't that be normal since when you shut the car off you cut power to the fuel pump and the pressure then bleeds down. Didn't you say it occurs about 20-30 sec after shutoff?

Kmartsoup

5-10 seconds. Before the mustang meltdown it would hold ~30psi for days before bleeding to maybe ~25psi.