jowo9

iTrader: (1)

Alright,
Well I've noticed in the last year or so, that when the engine/transmission is cold in my 4AT, I'll push the throttle in just enough to make the car downshift (usually at ~30mph give or take), and the car bogs briefly as it kicks into the lower gear.

I must emphasize that this happens at part throttle... so probably anywhere from the throttle threshold point of downshifting to ~80% throttle. It just bogs for about a second when the car hits the lower gear, and only while it's still warming up... the problem always disappears after 10 min or less. This may be a stupid question, but could it be that I'm using a less-than-perfect auto transmission fluid that might be more viscous than the car is meant for while cold? (I'm using Mobil Super Multi-Vehicle ATF)

What are some reasons as to why my car might be doing this??? (throttle body valve, tranny, tranny fluid, running rich with headers/exhaust? (seems possible... I've tuned for WOT, but obviously can't tune part-throttle with a VAFC II))

:::EDIT::: I suppose I should take a look at my Wideband while this is happening, and I can see if it's just spiking rich on these downshifts while the ECU lags to compensate... I'll do that tomorrow... but if that is the case, I can't understand why it'd only do it while the engine/tranny is cold.

Scottwax

iTrader: (8)

Could just be cold fluid not flowing properly through the valve body.

jowo9

iTrader: (1)

Oh ok...

Is there anything else it might possibly be? Anyone?

njmaxseltd

iTrader: (19)

A cold engine running a set a/f mixture?

Check or change your coolant temp sensor.

Could also be a slow MAF signal when it's cold.