Rough idle on start, doesn't seem to have any power at all. on 1994 Mazda B3000

Changed plugs, wires, rotor button, cap, pcv valve, egr valve, what else would create what I think is a power drain?

Asked by for the 1994 Mazda B3000
Start with the basics, check the compression and perhaps do a cylinder leakage test to ensure the engine is mechanically OK. Perhaps verify fuel pressure and fuel delivery volume. Check for a restricted exhaust and "water test" the ignition system with the engine running to make sure the ignition insulation is good. Check for engine vacuum leaks around the intake manifold. Has the engine run hot or been loosing coolant? Could the head gasket be leaking? To many possibilities just for me to guess without being able to look at the car first hand.
Thanks. Will check those things.