97 Tacoma 2.4 No comm with ECU - Running rich

Hello
Looking for some input. I have a 97 Tacoma 2.4. I was told it required a cat at purchase due to glowing red. I removed the internals of the cat and installed an extension for the 02 sensor. I noticed when the check engine light illuminates you cannot communicate with the ECU via scan tool or by jumping pins at diagnostic plug in engine compartment. I purchased a serviceable ECU only to have the same results. It appears when the CEL light comes on it begins to run rougher as if there was a load on it. It runs rich emitting black soot and water vapors, I believe the red cat could have been from a rich condition for the previous owner. I removed the vacuum line from the fuel regulator to ensure there was not fuel in it.
I have replaced plugs, wires,cap,rotor, fuel pump and recently replaced the injectors which aloud it to accept throttle when revved up, it would previously bogg when accelerator was depressed. The vehicle sat for 7 years , which I believe was due to this issue. I have read a few threads that had the same issue but never saw a fix. Any input would be appreciated