1.8t stumble/miss full throttle under 3300rpm

[bigrobby]

99.5 a4 1.8t mt 200k miles apr stage 1

when ambient temp goes below 60 degrees, my car will stumble/miss multiple time when under full throttle and under 3300 rpm (about 15 psi).
this is a new problem, my car has been configured this way for 4 years, 90000 miles. after 3300 rpm, it runs perfect.
generally when outside temp is above 60 psi, it won't have this problem. it's generally in 3rd 4th and 5th gear when engine is at max torque.
for instance, if i floor it on the highway in 5th gear, it will stumble and jerk in between 2700 and 3300 rpm.

when this first started, i put a new set of bkr7e spark plugs in. i've used these plugs for 4 years.
the only thing that has been replaced since last winter was the ignition control module (the thing on top of the airbox). replaced with made in USA bosch unit.

it feels WAY too jerky to be a boost leak/loss problem. but i've been wrong before.

what do you guys think??

thanks for the help

[bigrobby]

also, it's not my dual mass flywheel or a broken motor mount. my motor mounts are fine and that stupid heavy dual mass thing has been gone for years. besides, it doesn't just stumble one time. it stumbles at least once a second until around 3300 rpm is reached

[FNK]

Mass air flow?
Do you have VAG-COM?
Log group 002 at WOT (Wide Open Throtle) and note the max air flow (grams/sec).

Divide that number by 0.8 and you should have you number of HP. (A tuned car might not be applicable, but a stage 1 is)
If you are significantly lower than the hp you should have, the MAF has a problem.

Ex, the 1.8t of 150hp read 120g/s at peak HP, 120/0.8=150.

Also, you should read at idle around 2.50±0.5 g/s. (Read thoses values when the engine is fully warm, water temp above 80celcius otherwise the engine is in warming mode)

[bigrobby]

replaced all coil packs with some used ones i had sitting around. problem gone