The Daily Telegraph says the captain had complained about the left engine...
"The latest so far is the claims that the captain, Liao Jiangzhong, complained of “engine abnormalities” and requested an urgent inspection of the plane shortly before its final take-off but was rebuffed.
Liao Jiangzhong, the plane’s former air force pilot, is among 32 people so far confirmed to have died when the aircraft crashed into a river shortly after taking off from Taipei’s Songshan airport on Wednesday morning.
An unnamed “whistleblower” told Taiwan’s Liberty Times newspaper that Mr Liao requested a thorough inspection of the plane after noticing “engine abnormalities” during its previous flight.
The pilot registered the problem on a flight log, the newspaper added."
TransAsia plane crash: Pilot complained of ?engine abnormality? before take-off - Telegraph