my97 uk turbo has become jurky under heavy throttle and sometimes coming off the throttle it almost stalls ot gain idle only started after fmic fitted is it the mapping in need of tuning or could it be something else was told it could be maf
but changed this morning still the same???? any help please

 

MAF sensor gets blame for everything.
I am no expert but i reckon with any major mod you should , as you said, get the map set up accordingly