escort running rich

[BilLster]

we have a 88 escort wagon that started running really rich.

Pulled the o2 sensor black replaced it all 4 plugs supper carboned.

car still running rich after sensor plug change.

I'm thinking return line plugged or pressure to high as gas is now smelled as soon as the car starts before it askes the 02 sensor for reading's

so how do you test fuell pressure on a CFI unit ? should I be able to blow compressed air thru the return line ?

there are two adjustments screws under the back of the throttle body for the fuel line and return line and I've been told you can remove the top of the cfi unit and turn the inside to adjust fuel pressure ?but the person didnt know which way was down ?

someone else suggested a vacum leak but i couldnt find any.

thanks the top end screams but how often do we drive there.