Emissions diagnostics and TBI rebuilds

[NCali]

1987 2 wd 1/2 ton with a 305 tbi

can anyone tell me what causes and how to correct high emissions
like what causes high co levels and what to do about it?
high HC, and what to adjust to lower that, and how changing the levels of 1 affects the other type of emissions
also
  It looks like my TBI is leaking at the pressure regulator. I just read the artical on rebuilding the throttle body. Once you make the regulator adjustable how do you set the pressure to specks. there is no room for a gauge back there

[Irish_Alley]

a vacuum leak will confuse the computer and cause it to richening the fuel mixture. but lets start with the basics, does your check engine light turn on when you turn the key to "on" and is it on while the engine is running?

[VileZambonie]

High CO is an indicator of a rich condition. Post all of the results of your emissions test for a better analysis

If your fuel pressure regulator is leaking, fix it and you don't need to put an adjustable regulator in unless you are trying to increase output.

[NCali]

The check engine light now works as you describe. it was put on a machine but the guy saw it would fail so we didnt run the test so I dont have any numbers. He said the hc and nox were high and carbon monxide

The regulator does leak so I will put a kit in the throttle body