Need more RPMs

Greetings fellow motorheads. I'm a newbe to the site and have many questions about older Mustangs, Galaxies, Fairlanes, and other early muscle. What's baffling me the most right now is a quirk with a 98 Mustang 3.8, 5-speed that I bought really cheap because of some front-end damage and a stuck valve from sitting up for a couple of years. It only has 75,000 miles and has cleaned up really nice.
After replacing the fuel pump, I got her running and did a shakedown but found no problems. I set out on a short trip and about 30 miles from home, the motor started cutting out around 2,000 RPMs. By cutting out, I mean it chokes out to nothing. I limped back home, thinking some crud from the old gas had broken loose and was causing the problem, so I changed out the fuel filter again. No help. Removed the injectors and had them cleaned, no help, although now it chokes out around 2,500 RPMs, and finally replaced the fuel pressure regulator. Again, no help. Fuel pressure gauge reads steady 30 psi through the rev range. I don't have a code reader, so I'm just going on old skool logic. What's next? More fuel system diagnostics? Ignition? ????

Firstly... The fuel tank is NOT going to have any debris or junk in it.

Secondly, Drive or limp it to an Autozone or O'reilly's or some such auto store that actually will let you use their code reader, or rent it from them adn find out what the computer tells you.

I think your fuel pressure might be a bit low, but since it's constant you're probably safe there...

Ignition and timing is all coputer controlled...

Get a reader. That will help a lot.

Thanks, those are strategies I have considered but thought I'd put up the question here first, in case it might be something simple that I'm overlooking.
Re: trash in the gas tank, the car had set up for a couple of years before I bought and the gas had turned to the gunky varnish muck that clogged up the fuel pump. I cleaned it the best I could with alcohol and the new pump had fresh filters and of course was enclosed in the basket. I was thinking some gunk was in a fuel line and broke loose.
I can relate to your screen name of FE and going broke. I have a couple of FE projects -- a 67 Cyclone that will be upgraded with a 428CJ and a 67 Galaxie convertible that will be upgraded with 390 GT parts, bucket seats, console, quarter patch panels, etc. And if that's not enough to empty my wallet, I have a six-cylinder 67 Mustang coupe I'm considering for a V8 transplant and a 68 Mustang fastback shell that waiting for a 5.0/5-speed I traded for.
As I said before, I'll have plenty of questions.
Thanks again.