faster than you

Hello all

99 type R, standard apart from walbro pump and straight through exhaust.

The problem is as title states, the car seams to run lumpy and stalls at junctions, I've had it on a diagnostic reader, there is no faults at all, but the reader says the car is running rich at idle which would explain the stalling as it is getting to much fuel at idle..

Had a new MAF, which when unplugged makes the car stall, all pipe work has been checked.

Any ideas?

Thanks in advance