I have a 1994 Ford club wagon. Recently it had issues accelerating, almost like the engine was about to die. Then I would take my foot off the gas pedal and then push it down again and it would work a little better.
When it happens it seems like the engine is getting little to no gas for a 1/2 second, then more gas for a 1/2 second, then back to little or no gas again for a 1/2 second etc etc.
It does not happen all the time, usually there is a period of normal engine performance after starting the van. Some times pulling over and turning the engine off for a few minutes and then restarting will alleviate the problem.
So far we have changed, the air filter, fuel filter, spark plugs, spark plug wires, distributor cap. Also added fuel injector cleaner.
Have the fuel pressure tested. You have done everything my dad would have done (all the easy and cheap things), but it’s time to consider actual parts. Start with the fuel pump.