E85 idle question - occasional surge at a stop
 

I'm running the Motoeast flexfuel kit on an otherwise stock motor (stock intake/exhaust etc....).

occationally at a stop, my idle (with the A/C on) will bounce upwards from 850ish to 1,000rpm. It doesn't seem to fall down below 800 but you can see the surge upwards on the tach (and my Scanguage). I wouldn't call it rough as its something you see more than you feel (given its not dipping down).

I'm told this is basically normal, is this the injectors cycling to push more fuel due to the e85? My idle didn't do this on my regular 93 tune.

Love the kit and tune, otherwise everything is rock solid and I'm very happy with the power (193whp).

Just curious others experiences, not a deal breaker, just want to make sure I'm not missing something.

Pretty normal with a\c compressor cutting in\out to have small idle variation

If AC is switched OFF, can AC compressor still impact readings/logs? (thinking of how to make most consistent results/lessen variables)

I've tried shutting off the A/C and I occasionally still get the surge. I totally get that the A/C compressor and general idle characteristics mean idle is going to flux 100 rpm or so. Those kinda rpm fluctuations don't even register on the car's tach, but I can see them on my scan gauge.

Jumping up 150 rpm or so seems a little more unusual, which is why I was wondering if maybe I'm seeing something related to the injectors needing to push more fuel at idle on e85 than normal and that is resulting in the surge (could the port injectors be kicking in?).

Its not something I feel as the rpms never fall as part of the process to a level where the idle gets rough.

Mine does this a little when the AC is running. Doesn't seem to happen with the AC off though.