My 1997 4.6, 2wd, 5speed, with 140K miles.. This all started when I left my pickup at my brothers farm, for two months.. They ran fuel tank almost empty, lower than I usually run it. Filled up, and a block after, trouble, water temp pegged, oil light on, voltage gauge pegged.. and in limp home mode.. get home and check fuel pressure at rail, @15 lbs, idled ok, but all above gauges pegged and not overheated.. over the next weeks, cleaned 4 ground straps, replaced positive starter cable (it needed anyway).. replaced CHT under manifold. Low and behold the gauges all came good... great.. Now no spark at non COP plugs this after unplugging PCM and spraying with contact cleaner, one of many unpluggings and contact spraying s.. Then I'm asked if I disconnected the battery when spraying the PCM contact harness ... No I did not... I have power to fuses and relay... #30 on drivers knee panel.. I was told that PCM rarely go out,, but I think I screwed up..

 

It shouldn't even run when it's that low - minimum is 28 and 40 is normal.

 

You can call it a screw up if you wish but you have to stop going at these things on a wild *ss guessing streak because you can cause more trouble than the original you began with and are now into confusion.
If you saw low fuel pressure, why did you go on to other actions?
The motor will quite possibly idle at 15 psi pressure but would have no power otherwise showing there is no trouble elsewhere.
Since you got into so many other areas, you will have to address each one as a separate issue until all are addressed..
First, are you sure you have no spark?
If no spark, check fuse #30 a 30 amp. It feeds the coils and fuel injectors.
When you get voltage back at the coils and injectors with the key to RUN, then reseat the PCM relay to be sure it's not an issue.
Next, does the motor crank? If yes your good there.
Next, put a fuel pressure gage on the test port. Operate the key to RUN several times. How much fuel pressure registers?
If not up to about 35 psi, the pump is suspect ...and... tells you the PCM is alive..
If no pressure do you hear the pump run at all for a couple second at each time the key is operated to the Run position?
Each of these steps is proving out the operations as it should have been done before..
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As far as the dash goes, there quite possibly is a ground issue for just the dash as a separate problem.
Bottom line is you have to begin sorting out all the issues one at a time from the point your at now.
Remember the truck is 19 years old now.
Good luck.
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Or it may just be a plugged fuel filter.

 

First day above freezing here... I just want to get spark back,, the motor cranks over well.. But no voltage at the middle contact into coil back and no voltage at ether terminal of crank sensor .. I have power at PCM #30 fuse and relay under hood.. thanks to all help..

 

The coil RED lead is the power from the fuse.
You must have power on that lead.
If not, the lead back to the fuse is open.
Also the jnjectors get power from the same source so their red lead must have power, or no fuel.
Double check this to be sure of what the condition is.
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The Crank sensor is a Hall effect, and generates it's own pulses as the ring teeth pass buy, so you won't measure any static voltage on it.
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Check to be sure fuse 24 and 30 is good and that there is voltage present at the fuses..
Good luck.

 

You need to probe the test points on top of the fuses for voltage while installed, you can't just pull the fuses and look at them or ohm them out.

 

No 12v to the red lead at my coil pack,, So I had f150 towed to local Ford dealer.... They replaced the crank sensor and short connection loom to it.. $811 later, it now runs and now I will retrace why it low fuel pressure and has 90% power.. Ford mechanic said it was not throwing any codes, we shall see over the next week.... Thank you all for the help..