Have a flat spot at about 4500rpm, its driving me nuts !
1.8mk2 gti, k-jetronic injection system, 8 valve. Tried a few things already, new HT leads, plugs, removed and cleaned the airbox and all the "moving bits" (very carefully). I have not tried swaping out the coil, or checked the injectors. Also (not sure if its related) I had the injection system checked and tweeked (as the car was running very rich), and it made quite a difference to the MPG, but it would appear that the car had reverted back (slowly) to running rich, without touching a thing under the bonnet !!