King discusses Cujo in On Writing, referring to it as a novel he “barely remembers writing at all.” King wrote the book during the height of his struggle with alcohol addiction. King goes on to say he likes the book and wishes he could remember enjoying the good parts as he put them on the page.
Wikipedia agrees with you:
https://en.wikipedia.org/wiki/Cujo
He has also said this about Maximum Overdrive.
TBF, who wouldn’t.