E-030 + Poor Mileage + Bouncing High Idle At Startup

[Susana]

1990 Eldorado Biarritz Touring Coupe with 80,000 original, dealer cared for miles is driving me INSANE!
Please, HELP!
Here's what I can think of that may be important:

__The SES lamp would light and the ECM Code 030 would display since a long time now, but we went along, decent mpg / timely maint./no "real" problems after the dealer drilled out the EGR ports and replaced the EGR valve in response to the SES lamp- UNsuccessfully.

MONTHS LATER:
__Keys got locked in the car - on the seat - AAA jimmied the door and retrieved them.
NEXT MORNING:
__Warmed up the car, drove the morning routine, came home, parked. Nothing untoward.
SAME AFTERNOON:
__Car refused to recognize me from 2PM - 3PM, straight, 3 minute intervals.
NEXT:
__Towed to dealer for replacement of Ignition Lock Cylinder & 2 keys for $410.00
THAT EVENING:
__The car, which drove fine on the drive home from the dealer, refused to start in the driveway.
FOR THE FOLLOWING 12 HOURS:
_I tried every possible way to get the car going. It would not hold a jump over 5-10 mins. Eventually, I put another battery in it and drove to Pep Boys, thinking I'd just get a new battery and go.
AT PEP BOYS:
The car refused to crank for me, intermittently. Dealer said no NOT pay Pep Boys $200.00 to toghten the knuckle bots - drive it back and they would make it good.
MINUTES LATER:
The dealer showed me how I need to get extra leverage on the key to crank it all the way - it was my cranking of the key technique that lacked the leverage to turn the key on - ( opps! )
EVER SINCE:
__The code ECM 030 still lights, at times.
__The gas mileage is down from 26 to __5__mpg!
__The rpms at cold start up are erratic - and on the high side - 1400 - 1200, then, 1200-1100, then, 1100 -1000, then, 1000 to625 - 825ish - it takes FOREVER to get them down to a decent point for putting it in reverse, to back out the drive.
__It makes the tut-tut-tut sound - ( which is MORTIFYING in and of itself! )
TO FIX THIS I HAVE:
__New lifetime Bosch ignition wires
__New dealer supplied spark plugs
__New fuel filter
__New PCV valve
__New Air Filter
__New Distributor Cap
__New Rotor
__Throttle body - and behind the blades cleaned out very thoroughly
__Injector cleaner added to tank ( LUCUS )
__Done the "Go From 20mph To WOT" exercise at freeway on ramps - with ZERO emissions noted from the tail pipe
__Done the "When Battery Is Disconnected Idle 20, Put In Drive & Idle 5, Turn On A/C & Idle 5 More Mins" routine to reset the computer

An independent mechanic used a tester with a lamp in the handle on each of the plug boots at the distributor cap and found (3) injectors to be faulty. he then used a long screwdriver to listen to them, and had me listen, too. They all sounded the same, basically, to me. Still, he added injector cleaner, told me to add another at each of the folwoing (5) fill-ups and return to him for (3) - or ALL new injectors if the additive did not fix things.

Maybe the injectors ARE semi-clogged, but does that explain EVERYTHING? Even the ECM COde 030???
I would much prefer to find the senor(s)/components that are causing all this 5mpg grief and fix them, then, save up for all new injectors...
I'm an ovarian cancer patient with a totally disabled husband ( feel 2 stories at work and broke his head wide open, swalling spinal fluid, etc ) and 2 girls, 6 & 14 to raise on a CRAZILY reduced income of DISABILITY ONLY, so, FRUGALITY is key here, folks! I'm NOT a Tom Girl, but, from the Mother of Invention, I MUST do all of this that I can, to save us money...

I am at a loss!
Please, HELP!
Susana