Too much fuel, won't run right, help

[Zar7285]

1995 tbi 454 suburban. Every sensor on the engine has been replaced recently. Recently replaced the fuel filter and now it's dumping fuel into the throttle body. It was running somewhat rich before but mostly just at startup. Number one plug is fouled with soot and unburned fuel. Now when trying to start, it'll putter out after startup and die. Cap, rotor and wires are newer too. Plugs will need replaced or cleaned up obviously but don't want to do that until I fix the running rich issue. I have googled and searched here and everyone seemed to have slightly different issues and either solved it or never got a response. This seems to be a pretty common issue with these things and they're old, I figured someone would've found a permanent fix by now

 

[Gramps]

Getting hooked up to a good scanner with a live data will probably be the most helpful, however a few things you can look at without one:
Temp sensor (not the temp switch for the guage) these notoriously fail and when they do they default to showing -40* so the ecm does it’s thing and dumps a ton of fuel.
Easy to see this with a scan tool To confirm but very common non the less.
If that’s not it, I’d look at the fuel pressure - the spray pattern in the throttle bores should be 2 nice cones, And no dripping. You can rent/borrow fuel pressure tester most parts stores. Somebody else that knows more about the late big blocks hopefully pops in here with what the pressure spec is, I think it’s higher than the 10-13psi of the small blocks and earlier big blocks.

Check the timing, make sure it’s set correct and not retarded.

 

[Erik the Awful]

Diagnosis. There are so many things that can cause a rich condition that nobody on the internet is going to be able to remotely diagnose your problem.

The clues you need:
What's your fuel pressure?
Is your O2 sensor voltage swinging fast enough?
What does your temp sensor say?
What does your injector spray pattern look like?