car runs too rich didnt pass smog

[bshizzle]

i have a 90 4.5 fleetwood fwd and it is running too rich. wont pass smog because of it. i have most injectors replaced couple of years ago. did a tune up o2 sensor changed. is there anything someone could recommend before i take this to a mechanic shop and blow 100's of dollars.

my car also qualified as a gross poluter. the numbers it failed was at like 600 but was suppose to be at 120 or under.

[awadecki]

maybe a bad fuel pressure regulator?

[noahsdad]

Here's the list from the FSM for diagnosing a rich condition:

Run OBD diagnostic - any codes?

Double check oxygen sensor parameters and connections

if oxy sensor is within parameter value 0.00 to 0.63 V:

1) Check for restricted air cleaner or thermac valve operation
2) Check EGR operation
3) Check fuel pressure
4) Check for injector leaks
5) Check for vacuum leak to MAP hose
6) Check purge canister for proper operation

[behind-bars]

I just tried seafoam, says on the can it'll help pass emissions test. It cleans carbon out of the engine.

I would say o2 was at fault if was it replaced before the injectors? If it was one after the injectors it may be fine, Also was the car warmed up when tested or still cold?