On Sep 25, 8:22 am, GM...@wowway.com wrote:

There's no direct adjustment for mixture with the EFI.  The computer
is supposed to figure that out based on its stored tables and sensor
readings.  You need to find out where things are going wrong.

In no particular order:
-bad fuel pressure regulator (very common, but I thought it failed
open (lean) usually)
-leaking injector
-bad MAP sensor (I think a 94 460 is SD, but just guessing really)
-bad O2 sensor
-vacuum leak (wild guess here)
-something someone else can think of :)

What are you seeing that makes you think it is running rich?

Calvin