bad idle, pulling time, and burning rich

I have a 95 GMC Jimmy with a 4.3L Vortec. I have had an issue with the engine running rough for the past 3 months. Here is what I have done to the Engine:

Issues:

Burning Rich – O2 Censor is reading around 952 (On Idle) with no cross counts
Idle Rough – Computer is pulling time (even as much as –12.5)

Steps Done:

1 – Checked for exhaust leak > None found
2 – Replaced O2 Censor > Read the same 879 to 975
3 – Replaced Dist Cap, Button, Plugs, and wires > same issue
3 – Removed Intake (Carbon was cleaned off on right cylinders 2,4,6 caused by injector leak)
4 – Found injector leak > Replaced Fuel injector
(After this it still had the same issue except it would not burn rich at 5%+ throttle. The timing would also run correct at 5%plus TPS.)
5 – Cleaned EGR > EGR is functioning correct
6 – No leak found and Fuel pressure is correct

I am befuddled. It runs good at 5% or more throttle. At idle I do not see a reason why it should pull timing to that extent. It’s not because of the knock sensor, EGR, or anything else I’ve tried. Computer is doing the correct thing by dropping injector down to 80, but its pulling time and is still burning rich. I am grateful for any suggestions.

4. Found injector leak...did you replace only one poppet...or the entire CPI unit...?