completely normal. when you are off the gas the throttle plate closes, no air coming in, hence the no reading.

stoich is 14.7, so use that as your base. a nice conservative tune will be right around 11 at WOT. Usually dips into the 10s, general rule of thumb is dont want higher than 11.5 (im not a tuner, changes completely based on tuner, build, fuel system, parts etc).

idle should be right around 14.5-15 ish and not jump super lean or rich. partial throttle, as common sense would imply, should be right in between WOT and Stoic.

again, just general rules of thumb to follow. you have nothing to worry about it appears

 

I am not familiar with the EVO ECU specifically. But, standard ECUs cut fuel injectors when the throttle is closed in order to reduce emissions and protect the catalytic converter. That causes the AFR to go very high, beyond the AFR meter reading scale. Nothing to worry about under such conditions: with no boost and with no load.

Sandro

 

I'm going to be a troll and say that claiming "no air and no fuel" flows through the engine @ no throttle isn't entirely correct. There's definitely air being pumped. The AFR moves towards infinity because of the lack of fuel.

 

11.5 AFR is Maximum Torque at WOT

It bounces around a lot to be honest. You really only want to keep an eye on it at cruising.(should be around 15.3 +/- .5)

Have you checked your fuel pump relay? Mine acted weird.

I'm on my phone so I can't find it but whoever said anything higher than 11.0AFR is "Vented Block Territory" is a little far from the truth... I ran with a bit of knock and 13.2 at WOT because of a busted relay and my car is just fine. Not something to do every day, but still.

 

My relay is actually good. I mean, it's no blue relay, but at wot I'm around 11-12.

 

I've had bad luck with the aem afr gauge, it's very temperamental