Check cylinder head for warpage. See INSPECTION under CYLINDER HEAD under REMOVAL & INSTALLATION. Measure camshaft lobes across their maximum dimensions. Inspect for scoring and wear. Replace camshaft if not within specification. See, in this article, CAMSHAFT LOBE SPECIFICATIONS table.
NOTE:
For additional camshaft specifications, see, in this article, CAMSHAFT SPECIFICATIONS table under ENGINE SPECIFICATIONS at end of this article.
NOTE:
Camshaft bearings are NOT replaceable. If not within specification, replace cylinder head and/or camshaft.