Fuel pressure specs?

Please list the engine size when you have an engine-related problem. Rough running is usually the result of worn spark plugs and wires. Some GM engines do run poorly or won't even start when fuel pressure is just a few pounds low, but that applies more to truck engines.

Fuel pressure for the 2.4L is 52 - 58 pounds.
Fuel pressure for the 3.4L is 48 - 55 pounds.

Before you get too involved looking for elusive stuff, did you consider worn spark plugs?

Four pounds low on fuel pressure will not be an issue on other cars, but to rule that out on a GM product, when the rough running is occurring, look for the fuel return line where it is rubber between the fuel rail and the body. Pinch that off with a hose pinch-off pliers. Fuel pressure will increase if the pump is able to develop that higher pressure. That will prove the pump is okay. Those cause a lot more trouble than regulators do.

GM has had a lot of trouble with their fuel pressure regulators leaking, but that also applies more to truck engines. Pull the vacuum hose off at the regulator and look inside it. If it is wet with gas, replace the regulator. Pulling the hose off should also make the fuel pressure go up. If it does, the regulator is working.

Now for the more elusive cause of rough running on GM vehicles. Unplug the small one, two, or three-wire plug from the back/side of the generator. If the rough running clears up, I will discuss that in more detail.

I just typed a really long reply to explain it, but I thought your eyes might glaze over. I will post it if you are interested.

GM has a really big problem with their generators starting with 1987 models. They develop huge voltage spikes that can damage their internal diodes and voltage regulator, and interfere with computer sensor signals. This becomes much worse when one of the six internal diodes fails. By unplugging the smaller connector on the back of the generator, you are simply turning it off, along with any voltage spikes it might be developing. If those spikes are the cause of an elusive running problem, it should clear up on a short test drive.

AllData lists 52- 58 psi for a 2000 Grand Am with either engine.

1999 Grand Am 2.4L with EGR, and 3.4L: 41 - 47 psi.
1999 Grand Am 2.4L without EGR: 52 - 58 psi

Some numbers come up different depending on where you find them. The engineers can't make up their mind, and it appears some service manuals don't agree either. Years ago there were over two dozen part numbers for PCV valves for one model year. They only thing you didn't have to know to get the right part was the car's paint color.

The best thing I can suggest is what I mentioned about pinching the fuel return hose. If fuel pressure jumps up, that proves the fuel pump is able to develop a higher pressure. At that point, if pressure is too low, it's either a pressure regulator problem or a volume problem. Be aware Chrysler and GM fuel pumps fail in very different ways. GM pumps almost always start up, then they slow down when they get hot after driving a while. Most complaints refer to power loss or stalling while driving. Those failing pumps often work again after cooling down for a while.

Chrysler pumps fail by failing to start up, leaving you sitting in the driveway or parking lot. Banging on the gas tank sometimes gets them going, then the same problem could occur at the next start-up, or not again for a few months. Once they're running, it's just about unheard of for one to quit while driving unless there's a wiring or connector terminal problem. Fuel pressure problems rarely enter the equation on Chrysler products.

With GM or Chrysler models, before you condemn a fuel pump due to low pressure, perform a volume test, especially if a problem develops after driving a few miles. A common cause of volume dropping off is a plugged strainer, or "sock" on the fuel pump housing. Don't waste your time replacing a fuel filler on a Chrysler product unless it has rusted out and is leaking. They commonly last the life of the vehicle. The same is not true of those strainers. A clue the strainer is plugged is the engine will run best at highway speed and when accelerating. Stalling will occur repeatedly when the highest volume of fuel is being pumped, which is during coasting.

GM fuel filters do need to be replaced periodically, but the clues are different. Any problem they cause doesn't get worse the longer you drive, like it does with a plugged strainer, and the engine won't run better when it's cold.

Here's links to some articles you might find of interest:

https://www.2carpros.com/articles/signs-of-a-clogged-fuel-filter-in-your-car-symptoms-to-watch

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let me know if I missed anything.