AC Delco Iridium gap size (should they be gapped?)

[z7111]

I know it should be .040 but I bought the original equip plugs and the gap was about .030. I opened them up to .040 but I swear the fuel econ display shows less on takeoffs and up hill with cruise control. Should I have not gapped them? Or could it be that I flattened or altered the electrode with my gapping tool. I use the standard coin shape gap tool.

Ive got 120k on my 07 and the wires and plugs looked original. I replaced both. My expectation was that I would see a slight bump up in economy.

 

[z7111]

Has no one here changed their plugs? I cant be the only one...lol

 

[Tewhite]

Changed the plugs in my previous 2003 with iridium AC plugs. Cannot remember the exact gap, but was over .030 for sure. The old plugs were eroded and over size by fair amount. New ones were spot on.