1994 GTP struggles during acceleration

3.4L V6 with Hydra-Matic 4T60-E. The trouble began about three months ago. Engine died after fast acceleration. It did not reoccur for several weeks. But slowly but surely it became more frequent. Now it is almost a guarantied to happen every time I drive the car. Typically stumbles when I depress the accelerator to start moving, it will clear till about 20 to 30mph, stumble and surge, then pick back up, it will reoccur at about 50 to 60mph. This can be very nerve racking, especially when it happens while merging onto the highway during rush hour. When the engine bogs down, the only way I can get power back is to floor it and hope for the best. After moderate to hard accelerations the engine often dies. I took it to a transmission shop; they gave the transmission a clean bill of health. They clam it?s a fuel supply issue. When in park or natural I can rev the engine up to max with no problems. It seems to only act up when the engine is placed under a load. On the rare occasions I do get a check engine light. It does not illuminate during the next start. Any thoughts?

thanks