first i'm a new member and want to say hello to everyone, my problem is my 94 deville 4.9litre was smoking (black/ rich) really bad during start and while driving also using gas like crazy. i assumed the o2 upstream sensors so i put in 2 new ones. the car seemed to improve slightly as both were clogged with carbon and so forth, i also pulled and cleaned the sp/plugs as they were fouled black as well. these items by no means took care of the problem just slightly improved the issue. my question is do you think the ecu need to be replaced

 

how about fuel filter ?

 

i be looking at the temp sensor for the cooling system.
it sets the ECU for fuel delivery, rich or lean.