General 1998 2.0 EL - engine dies at 2000 revs

[Richie-Teesside]

Engine revs up to 2000 rpm then cuts out, seconds later it cuts back in and revs up to 2000 again. Before this started happening it would cut out whilst driving for a couple of seconds then pick up again. The last thing I had done to the car was a new exhaust fitted a couple of months ago. Just after having it fitted the car tickover was very high but that lasted for just one journey and cleared itself. No dashboard lights on. Help anyone please.