What is the proper gap for a spark plug in a 2003 5.3 ? Using ac delco professional 41-110 iridiums. Book says .060, but out of box are .040, which is the gap for 2004 to present.
Gapped one at .060, seemed to really take the grounding electrode out of line with the center electrode. Re- gapped at .040, installed all 8 at .040. Runs fine. The set I took out were at .060.
Gapped one at .060, seemed to really take the grounding electrode out of line with the center electrode. Re- gapped at .040, installed all 8 at .040. Runs fine. The set I took out were at .060.
