When accelerating in my 4x4 sapphire im getting a backfire with lots of smoke which sometimes cuts the engine out. This happens at around 3500 to 4000 revs (just about when the boost comes on) and in every gear. Sometimes when the engine cuts out it wont start again straight away and needs turning over for a couple of mins. Apart from this the car runs perfectly with no other problems what so ever!!

Unfortunately im out of work at the moment and cant afford to see a specialist so wondering if there was anything i could look at myself. Any help would be very much appreciated