running problem


my sporttrak 1.6 runs at 2000 rpm constantly.when going up an incline it cuts out and splutters and looses power constantly but only on has just started to do this as i live in a very hilly part of wales.any ideas what it could be?ive already blew out the carb with an air line but still no joy.any ideas please as it is the first diahatsu ive ever owned and love it to bits