My fit finally seen the full blast of winter its -25 deg celius right now and this morning i notice my throttle seems lagging. next winter i'll experiment with denso iridium plugs see if that helps.

 

As opposed to the NGK iridiums that are OEM?

lets see... -25 * 9 / 5 + 32 = -13 deg F

yup. Cold. (I only understand celsius when it applies to computer component temps or kelvin as elemental melting and boiling points)

Hey thats how cold it was last year when my ebrake handle's cosmetic cover broke

 

its odd to change plugs. i would think you may try checking air intake filter firsthand.
could also be a faulty sensor down the line.
Just throwing some ideas out there.

 

Bought this car used, 32000k when i got it. I'm pretty sure the plugs are still oem. but i'll try denso iridiums this time and see what's the fuss all about.

 

plugs? how about full synthetic oil? did the lag stop after it warmed up?
just wondering...........

 

I'm already running castrol syntec. but i think its still lag because of these electronic throttle controllers i notice it picks up once it warms up.