GM began updating the LS series almost immediately upon debuting it, and by the early 2000s, the company was producing the 5.3-liter LS4, which first dropped in the 2005 Pontiac Grand Prix GXP.

The LS4 engine's compact size and transverse mounting make it as good a candidate as its cousins for swapping into other cars, but the LS4 was plagued by some common problems, some of which have ...