Auto Parts: 1990 buick reagal custom, buick reagal, diagnostic connector

Question
when i got the car it stumbled a lot and hesitated when coming from a stop. also when sitting still it would want to die. recently i could not go over 38 mph on the highway pulled over checked all the fluids and they were fine. car started back up and after about a mile it woke back up and ran fine for 2 days then it stalled like it ran out of gas. it wouldn't start  so i pushed it home. dad came over and bleed the fuel through the place where u check the pressure. it ran back to his house. we then changed fuel filter tried to clean fuel injectors, but were unable to. we cleaned throttle body now it runs great stumble and hesitation is gone, but it only has 20 lbs of pressure with the key on and it acts like it is out of gas when the pressure gets up to 38 where it is supposed to be when not running. we think the pump is ok, and now believe it is crank sensor. i'd appreciate any advice u could give. car died 6 times on the way home from work so i can't take it for diagnosis. thanks a lot.
sincerely james.

Answer
    You didn't say, but I'll bet this car is a 3.8, isn't it?  They had so many problems with these cars it wasn't funny.  I went round and round with one that we never were able to adequately diagnose, the only one I ever gave up on (well, actually the owner gave up, but it's the same thing).  First, a complete ignition tune-up is in order: six new plugs and new wires.  Then a good scope should be attached to the car and it should be run through its paces to see if there is any regime where it doesn't function properly.  If the mechanic has one of these new solid-state hand-held scopes, he can hook it to the engine, plug it into the diagnostic connector, and go for a drive while looking for anything out of the ordinary.  If you let him change the plugs, as well, he can look at the old ones and that will help with diagnosis.  These problems are almost always ignition-related, but he can check the fuel injection performance while he's got it hooked up.  If poor injector performance is suspected, you can clean them but, if I remember correctly, they are fairly cheap to replace with new ones.  The problem with these engines is that they are big enough and tough enough that it usually take two or three things failing at once to make the owner notice, and that makes diagnosis very difficult.