hi, really need help, had engine warning light coming on took car to dealer where they said the air mass sensor had gone, the car was running fine just this light on the dash, So i purchased a air mass sensor and fitted it myself and took back to garage to have computer reset. Now no lights but its running like a absolute pig, chugging and loss of power then a sudden surge of power, its also ticking over around 1000 rpm when warmed up, can anybody help before i have to take it back to garage to be charged yet again to put it on computer. thanks chris.

Was this a genuine MAF sensor or a cheap copy?

The obvious thing to do at this stage is put the old one back.

No it wasn't a genuine maf sensor, oh and just come back in the car engine warning light has come back on !!!!.

Take the electrical connector off the maf and see if it runs better. The Ecu will use default values and guess air imput. If it does run better disconnected its the maf. So buy a genuine one.