'94 Buick starting/stalling problems can't be diagnosed!

I’ve taken my '94 Buick Park Ave. into the dealer about 5 times in the past 3 months and they cannot diagnose/find the problem with the car. Most mornings it takes several times to start the car. Once it has started, I let it run for 5-10 mins. As I’m driving, on acceleration the car will sputter, the change oil light will come on for about 5 seconds and then the car will continue accelerating. It’s always the same combination of sputtering on acceleration, change oil light briefly. A few times after the sputtering, the car will stall. I was told that low fuel pressure was the problem. I had the fuel pump replace, but that didn’t help. I’ve had fuses, spark plugs changed and a new battery. Buick told me that they aren’t picking up any codes and so it’s impossible to diagnose without the codes or check engine light on. With the car stalling sometimes when I accelerate, I’m very worried to drive my car. Any help would be appreciate. Thank you

You may be having a problem with the alternator. To see if that is so you could try disabling it for brief time to test that theory. Pull the connector on the back side of it and then start the car and go for a test drive.

You need a reputable independently owned and operated shop. The dealer is apparently not interested. This one should be readily diagonsable. Even without codes.

How was the determination made that it was low fuel pressure? Was the fuel pressure regulator tested? If not, the regulator may be bad.

Has anyone checked the temp sensor?

Assuming this '94 is TBI, has anyone checked the injector? The injector and its spray pattern can be checked on e bench test setup.

Has anyone put the ignition system on a scope? An oscilloscope will show the actual traces of the spark pulses and a whole lot can be gleaned from them.

One of the problems that I am having is that I do not know of a reputable mechanic in my area. I have talked to 2 other repair shops that were recommended to me and I was told by both of them that if a code cannot be found, it is really trial and error in what’s wrong with the car and it would be a challenge for them to diagnose the issue as well. The car is currently at the Buick dealer for 1 last time to see if anything can be found. I was hoping that I could get some help from someone in the forum to at least know what to say to the mechanic.