This/these (all code and images) are for a 350cid/5.7L V8 engine.
Other engines use a combination of TPS% and MAP/MAF thresholds to initiate both PE and AE, and some can activate sooner and more often than this example. It's always best to check what you've got and not assume what's happening. Smaller engines or engines in an under-powered combination tend to be calibrated for earlier enrichment activation. Some people think that it only happens at WOT, but that's not true. This is a case where good data-logging and/or a WBO2 display can be very revealing if the data capture and display has a quick update rate.
EGR acts like a buffer in the chamber and so increases the requirement for enrichment fuel under conditions that necessitate PE or AE. Luckily the factory calibrations (usually) already overshoot the added fuel requirement by 15% or more. MPFI systems can usually get away with amazingly small amounts of AE, and a reduced amount of PE over a wet-flow system like TBI.
The amount of PE and AE can be further reduced by reducing the spark advance - basically taking away the PE spark adder. Power and response are reduced, but this is common-course for many eco-mods.
Here's a shot with some of the PE and AE qualifiers.
http://i702.photobucket.com/albums/w...EAEscreen1.jpg
