1999 Ford f-250 5.4 efie help

I need some advice on how best adjust dual efie. I have a digital dual efie I bought on ebay and have installed and tested connection so that I know it is hooked up properly. I have been told a .200 mv increase is a good starting point but I am wondering what everyone else using efies have been using. I am running about .8-1.0 lpm on my smack booster. How do I know when I have increased efie too much etc. I connect my meter straight to digital efie so it is very easy to increase in small units unlike the analog type efie.

You're starting off on the right track, I would run each setting for a hundred miles or so before making further adjustments. Basically, you want to find your best mpg without tripping any CEL codes or raising your EGT (exhaust gas temp) high enough to damage your engine.

Mpg is by trial and error, there will be a point where further leaning ceases to increase power (and hence mpg) and power starts to decrease. This is the sweetspot you must patiently look for.

As for avoiding high EGT's, the best way is to buy and install an EGT gauge. The ASE's on this forum should be able to give you a safe EGT limit for you truck. Some telltale signs of high EGT are pre-detonation (sounds like someone shaking a tin of nails under your hood) and rough engine running. You can also routinely pull a spark plug and check it for signs of over leaning. You should be able to google some pics that will give you a visual guide of what to look for here.

Russ.