Latest service on 2014 Polo came up with error codes - timing angle retardation on cyl. 1 to 4 as well as codes for misfires on cylinder 1 (0 of), cyl 3 (1), cyl 4 (68 of) and cyl 6 (?) (0). Mechanic suggests timing chain tensioner is faulty and need to replace along with timing chain. Only 68K km on car driven by wife. Engine can be slightly rattling on start up but quiet once oil gets to the top of engine. Wondering whether anyone backup mechanics costly fix or suggest other areas to investigate. Thanks