Up early this morning and checked the #1 plug. Had become loose as was not at tq spec. Drove to my shop and ran great all the way.
Removed the #1 plug and checked the threads against another plug from the same box this one came from. Over here we get plugs in a 10 box and I always keep the 2 extras as spares. Under a magnifying glass it was easy to see a difference on the threads. Changed the plug with one of the spares and will see what happens on the drive home.
Don't really like all these Chinese A/C Delco parts but market doesn't have anything different that I can find so may have to go to a different brand.
