2000 Firebird V6 Gas Smell After New Fuel Pump

It sounds like you may have clogged cats or pre-cats. Is this a V6? The pre-cats can get super hot and basically melt the catalyst material. This isn't a permanent fix, but jack the car up and pound on exhaust pipes before and after the cat converters to possibly shake out some of the clogging. You may also want to put in a fresh set of spark plugs.

the items that cause changes in the air/fuel mixture are
Heated oxygen sensor( in the exhaust manifolds before the cat converters
Map sensor
Baro sensor
Maf/vaf sensors
intake leaks ( vent on canister , vacuum hoses etc )
failed cat converter blocking exhaust system
The first place I would look at is the heated oxygen sensor(HO2S) as it has rather delicate wires that regularly fail and that causes erratic messages to the ECM

there are 2 sensors in the system
one is a heated oxygen sensor (HO2S) in the exhaust manifold / pipe before the cat converter that reports the exhaust gas composition to the ECM so that fuel/ air ratios can be adjusted
if that one is faulty it is most likely the reason for running lean or rich
the second sensor is the oxygen sensor (O2) which is after the cat converter and reads the results of the cat converter cleaning the exhaust
you may have to replace both the sensors to get a clearance or replace the cat converter as well as the HO2S unit

the catalytic converter being clogged would cause the car to die! How does the car react when you push on the gas?

poss ur map sensor is going bad

It sounds like you might have a clogged catalatic converter on the exhaust system.

It can be related. Was this a real highflow like a maganaflow or catco or was it one of the straight through designs? if you can see through it, even if it is marketed as a cat, it isnt.

Neither cat nor sensor.
You have a leaky fuel injector (stuck open).
Black smoke is unburt fuel.
Obtain a mechanics Stethoscope (like a doctor's steth, but has a rod onthe end instead of a disc).
You will find the faulty injector quickly.
Best to replace it.
(By the way, white smoke is Water and blue smoke is oil)

try a new catylatic converter,If it only goes 55 m.p.h , or under heavy strain,thats usully what it is.

Possibly a weak fuel pump, idle air control valve, vacuum leaks, or loose or damaged wiring in the ignition system. Check for vacuum leaks first. That's the only one that won't cost anything. Make sure all intake bolts are tight, and all hoses are connected properly and in good condition.