Have you tried seeing if there are any loose connections to the AFM as if this didn't register the increased air then it wouldn't increase the fuel
I'll check the TIS disc to see if it offers any simple checks to do otherwise you may have to see if any fault codes come up that a dealer can identify
I'll check the TIS disc to see if it offers any simple checks to do otherwise you may have to see if any fault codes come up that a dealer can identify