Whatever the problem, remember that auto manufacturers do not make their own parts, the parts are made by other people and the appropriate part number and markings are applied. There are only two vehicle manufacturers that make their own parts and those are performance parts, Toyota and Harley Davidson. Everyone else farms out their parts.
Off topic but sorry to inform you I made thousands of Pistons for the HD Screaming eagle line.
My Brothers largest customer is Toyota/TRD both lines
Virecit Vulnere Virtus.
91 Silverado, 350, To many more mods to list.
Left over 09 Cobalt LS,12/1/09 , 5-speed, Victory Red, Eibach Sportlines springs, Eibach Rear Bar,
ZZP Mid length Header Gold Poly Ceramic coated by Polydyne, with ZZP Stainless downpipe and
High flow cat. GMPP Cat back exhaust.
GMPP. CIA. Removed Air box Silencer.
TWM Short Throw Shifter.
Poser mods, O.E. Rear wing, Limo (58% I dunno) tint on rear and sides,Eibach front bar, Strut connector.