I have owned my 99T turbo since new without any problems. Just before Christmas I removed the battery for a charge because it was nearly five years old and a bit sluggish. I know that disconnecting the battery resets the ECU. Since reconnecting the battery the car has run absolutely awful ? holding back in the lower rev ranges (2000 to 3500 revs) then suddenly surging ahead, plus occasional intermittent holding back at motorway cruising speeds. I have disconnected and reconnected the battery a few times followed by long periods of running to give the ECU a chance to relearn. During this period I also fitted a new battery and my dealer has quickly checked and reset the ECU for me but didn?t find anything wrong. However, he did suggest that it might be a spark plug breaking down and assured me that no damage would occur if I waited until the next service in a few weeks time. I checked my service invoices and the plugs have only done about 10,000 miles so I doubt spark plugs are the problem. Last week someone suggested the problem is common on the 99 car after the battery is disconnected, and that it is almost certainly the air flow meter. What worried me though, is that he went on to say that if it is the airflow meter, then this should never have been left as irreparable damage can occur.
My questions are:
Has anyone else experienced this problem
Where is the air flow meter (is it that probe in the large plastic air intake tube just after the air filter box ? I thought that just sensed the air temperature)
Can the air flow meter be checked without having to purchase one and is it easy to remove
Is there a way of checking if the engine has been damaged in any way (before Christmas I was close to spending at least 2k on a ECU re-map and exhaust, but now I am not so sure)
If it is the air flow meter, then what I find strange is how something can be faulty perhaps for years but only cause problems and damage when the battery is disconnected.
