Hi there, ive got a problem with my 1998 seat alhambra 2 litre petrol, it sounds like it is misfiring or blowing when idling. Ive changed the plugs and plug leads, changed the air filter and done an oil and filter change. Ive also had the exhaust checked of which there was no problem. Ive been told it could be the air flow meter which i was quoted 250 pounds to replace. Does this sound about right? Any help would be greatly appreciated. Thank you