dragonspiritdesign

i finally got round to changing the oil+oil filter in my 1994 subaru import sti today and while i was at it i reset the ecu.
after putting the clamp back on the battery and warming the car up i took her out for a spin i and all was well so i gave the motor some welly from standing start and got to 3rd and all was ok then just drove normally off boost.
2-3 mins later i accelerated hard and i got some serous judder and hesitation in 2nd and 3rd.
it only happens on hard acceleration not slow.
im a bit worried i did some damage on the standing start can anyone help please?