Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
You will want to check the fuel pressure and make sure that it is not low.
Also, the fuel filter, that it's not clogged up or restricting the flow of fuel.
If they are both ok, then you might have a problem with the exhaust system being restricted. You can have an exhaust back pressure test done on it, or you can take out the 02 sensor that is closest to the engine, JUST AS A TEST and see if it runs much better. If it does, that means the the exhaust system, (most likely the cat) is clogged up. Thanks
That's all I can think of on it. Let me opt out and we can relist the case to see if there may be another expert who may have more insight as to what it may be. Thank you for your patience.
HelloCustomer Super mechanic dropped me a note, to check in if I had any other ideas. I do. Take a blue propane bottle like what you would do to sweat pipes. Run a hose into the intake via a vaccum hose or some other point of access. Feed propane in and see if that allows you to rev the engine up. It's possible you did have bad fuel that had debris in it. The finer particles may have made it through your filter and restricted the fuel injectors. If the engine responds to the propane, I would suspect restricted fuel injectors. Let me know what happens.
Your JA Expert,