'02 ML320 (163.154), 65K miles... has had a recurring fault where the engine seems to hestitate on acceleration. The vehicle has been seen by the local dealer on 3 separate occasions for this complaint, yet the fault persists.

On the last two visits the dealer flashed the engine control module, performing "31WLT40" and "275WLT40".

Any idea as to what these numbers refer to?

Thanks.