Runs like Crap in the Rain!
 

When it rains out, my car is down easily 100hp. It runs like complete and utter (forgive the expression, but nothing else would suffice) dog_shit. It idles fine, and throttle response is okay, it just has no power. It feels like stg3...maybe, as soon as it gets damp out. The engine runs better on a 30*c day when it's dry than it does on a 10*c day when it is wet.
Why would this be? I thought engines were supposed to run better in the cold and wet? Only thing I can come up with is that the moist mixture takes longer to burn, and the ECU has yet to compensate for this by advancing ignition. But how can this account for 100 freakin horsepower???
Thanks,
-Cm
P.S I'd put this in the mod's section as I am tuned, but, it always did this.

evap issue

What do you mean by this? Is it making the mixture too rich? Is it sucking in water from somewhere? I often run with the gas cap loose because sometimes it will attempt to collapse the tank with vacuum.
-Cm

I do think you're on to something. I've been paying more careful attention and have found much better performance with a half tank or less. If I turn purge control "off" in T5 suite, the AFR goes wicked rich--especially during warmup. That doesn't make sense IMO, because the purge valve is a normally closed solenoid, no? With it shut off, the engine shouldn't be sucking in any fumes..
:???:
-Cm

disconnect the evap line going to the tb and cap the port on the tb let the evap line vent