Buick/Olds: drivability, coil pack, fuel pressure

Question
ok here is the deal i am working on a 1987 grand national... once it is warm it misses badly but only under load ( brake torcque included)  at apx 2500 rpm i have checked fuel pressure at idle and under load... at idle it is about 30 psi and underload it is about 36 psi    it is gettting a spark at idle but i am not sure at load i have checked relays and wiring and i am stumped any help would be greatly appriciated..... it just had the coil pack replaced about a year ago one relay had a loose connection i plugged it in and it still misses just not as soon

Answer
I dont have any specs here at home but I think your fuel pressure is low. If I remember correctly it should be about 38-42psi running.
Usually a miss under a load is ignition related. Could have worn or cracked sparkplugs, arcing plug wires, cracked coil, etc. Take a close look at all of the ignition parts. That is probably where your problem is.