Ford Repair: intermittent engine problem, marine corps helicopter, helicopter mechanic

Question
Mark, I have a 1992 Ford F-150 with an inline 6 fuel injected engine.  The vehicle has 180,000 miles but the engine has only 30,000.  However, I don't know if the engine accessories (injectors, pumps, etc...) are the originals or not.  Here's the problem: about two weeks ago I was sitting idle at a stop light and the engine rpm jumped by about 2000 and immediately settled back down. It's never done this before.  A couple days later it began experiencing very rough idles especially right after starting the engine.  I could keep it running by "working" the pedal but it was difficult.  When I depressed the pedal more it seemed to run properly but when the rpm's came back down it got bad again.  Then all of a sudden it would start running perfectly.  It's been doing this now for about 10 days and seems to be getting worse.  Some things that may be of importance are: when the engine has these "attacks" the "check engine" light comes on immediately and when the engine goes back to normal the light goes out.  Also, when I switch the ignition key to "on" the fuel pumps (dual tanks) come on and stay on; I've read that they are only supposed to come on for about a second after switching the ignition to "on."  In the rare instances that the pumps shut off after a second or so the engine starts and runs fine until the "check engine" light comes on and the engine goes crazy.  Also, when the "attacks" occur there is a great deal of dark smoke and a heavy odor of fuel in the exhaust but when the engine runs fine neither of those things exist.  I am a former Marine Corps helicopter mechanic and currently work on a UARA late model race team so I SHOULD know how to fix this but when it comes to fuel injected systems I'm completely in the dark.  Any help you can provide will greatly appreciated.

Jay

Answer
can be alot of things but i would check small ground coming off negative battery cable first-look for all grounds and powers and see if connections are good.-sounds like ecm may be loosing ground or bad computor-take a volt meter go to throttle sensor wires with vehicle running check orange wire should have 4.97-5.01 volts contant on it. (would be nice if truck was acting up) if it is bouncing 5-9 volts and grounds are good you probably have a bad ecm. black wire should read .002 or less and green wire should read .8-1.0 volt if these readings are not close let me know. what you get.