I have a 2003 Impala with the LA1 3400 That is running really rich I think it needs new Air filter and The MAF cleaned and the throttle body may also need cleaned opinions on this.

How do you know its running rich?

smell gas in exhaust while engine running so I feel it is running rich I think its an induction Issue it also uses gas more quickly and if its not getting air the computer will componsate making it rich if its not induction its exhaust and the cats or more likely one of the o2 sensors may be bad

If it was the intake system, you would be getting P0300'*. You might have a bad FPR dumping fuel right into the intake.

Had a problem like that but much worst was dripping gas out the tail pipe and smoking like a bad head gasket barely running.
It was caused by fuel injections stuck open
Never saw anything like it replaced all of them to be safe

yeah it runs like crap its loud and has no power

Test the fuel pressure regulator unplug the vacuum hose going to it for a min or so and see if any gas comes out of were the vacuum hose goes on the fuel pressure regulator.
If it does the its bad and its sucking gas in that way.

I might get a new engine from the recycling yard and rebuild the transmission.

How is it loud? Is there a way you can post a video of it?

Have you also confirmed the catalytic converter isn't plugged up?