91 gtst running lean

[RagingPanda91]

I recently installed new spark plugs, and have noticed that my afr is quite a bit leaner now than it was before. Does this mean I need a tighter gap or is it something else entirely. Once cold start turns off my afr is around the 16.5 to 17.2 mark at idle, prior to these new plugs it was exactly 14.7 at idle, and at full 10 lbs boost I run under 10 afr, now Im more like 10.9 11.5. The plugs I installed are the same as what were in this car prior, ngk BCPR7E-11 which is 1.1 gap. Just as I was writing this I checked the gap on my previous plugs and they are at .8 which I read was mainly for if your running 12lbs boost. Could anyone help me on this....

[Skym]

Lean = check fuelfilter, fuelpump. If happened after changing sparkplugs, check for an intake airleak close to or on throttlebody. There's a little joiner hose that runs next to throttlebody that sometimes is overlooked when putting intake pipe over top of engine (J pipe) back.

PFR5A-11 is stock on RB20DET (rich tune, cooler cylinder temps hence hotter tip plug is used). With breathing mods like intake, exhaust, small turbo upgrade or FMIC instead of turbo upgrade the PFR6A-11 gapped down to 0.8mm (leaner tune, high cylinder temps hence colder tip sparkplug is used) sparkplugs works.

[RagingPanda91]

Hey I regapped my new plugs back down to .8mm and that fixed the lean problem. I have just recently replaced my fuel filter as well, but I do know the clamps on my intake pipes are all weak, well be getting new clamps and couplers very soon. Thanks