1995 Pontiac Bonneville Engine driveability problem

Engine Performance problem
1995 Pontiac Bonneville

1995 bonny, it is obd1 with obd2 dlc and random other parts. Had been siting for a few years, put an ecm in it because the alt wasn't charging, fixed it. It started acting up and running rough soon after, diagnosed it as a cam sensor, installed a new one and released it to the customer fixed. She drove it for about 225 miles and it started running very bad so she brought it back. It will start right up then die, I can keep it running by playing with the pedal sometimes and if I can get it into the 3 to 4k rpm range and vary the rpm's by about 500 up and down for a little bit, it will come out of it for about 30 seconds, then go back to cutting out and will die within about 15 seconds. Fuel pressure stays at 50psi while running and goes to 60 when it dies, normal. One code in it, prndl switch malfunction, unrelated. Timing light flashes look like normal when car is acting up, no erratic pulses. Exhaust is not plugged up, has a new cat. When it first messed up on the lady it had a mass airflow sensor failure code in it, they replaced it with no change in symptom. All other data on the scan tool looks normal. I'm stumped!