Fiat Ducato Engine Management light

We have a motorhome on a Fiat Ducato , it's on a 57 plate with 16,000 miles on the clock. Recently the engine management light has been coming on once the engine is warm and she kangaroos every so often. Sometimes chugging! We took it into the garage( not Fiat) and he plugged her in and reset the codes. Next time out was fine for 10/12 miles then it started again. She is booked again in a couple of weeks for checks but I was just wondering if anyone else has had this problem??? Incidentally this last weekend she was fine on a 50 mile trip home( no light at all!!!)