1994 ford ranger 4x4 4,0 it idles good but when going down road the check engine light comes on within 20 seconds acts like it is flooding out loses power let off for a second and then runs good for couple mile but at any time if you put throttle to floor within lastinch or so same reaction any ideas

coil pack is dropping fire after it heats up

check ignition pick up its in the distributor. its responsible for spark in the plugs

You can hear it running for about 1 second when the key is switch to "ON", it is a very low pitched "Humming" noise. The pump is inside the fuel tank and it is best heard by removing the gas cap and putting an ear close to the filler hole. The symptoms you have are most likely not a fuel pump. Rangers in this year are prone to problems in the engines wring harness. This is a very DIFFICULT problem to track down, and i say this from 20 years of working in a Ford dealer as a tech, this type of problem was my everyday bread and butter..

Ford OBD Diagnostic Trouble Codes

Inspect / replace the idle sensor.
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Take your vehicle to AutoZone for a free "check engine light' analysis and ask for an explanation print-out. Have them reset the PCM (check engine light).
Let us know the code and summary of the print-out.

The mechanic should check on the idle .Because the Idle of the truck is adjusting by it self . That causes the truck to stop .check the Idle then lock it up to so that it will not adjust until it will make the truck stop .the main reason why the truck stop and pressure guage going down steadily is that no fuel enters the fuel pump when it adjust Idle by it self . It adjust by closing way or blocking the fuel to pass and go to the engine.then the engine dies .

either fuel filter or fuel pump...replace filter since its cheaper. 6-12 dollars at autozone

Check exhaust compression. Remove the O2 sensor before the cat and see if there is an increase in performance.

did you run a fuel cleaner?