AFRs all over the place.

[goatnipples2002]

I can't figure out why my air fuel readings are not stable at idle or any rpm. I can get a vid, but they bounce from 13-17 and anywhere in between. They haven't been stable since I started this damn build. I am starting to believe it is not the megasquirt, injectors or aem wideband. I changed so much that I feel like I am chasing my ass and getting nowhere. Mod list at end.

When I adjusted my lifter preload I only added 1/8 of a turn for fear of hanging a valve open. I will add more tonight, most likely another half turn. Could this have an effect on AFR?

Plugs were gapped real low (.020ish). Could a misfire cause these afr readings?

I have bone stock lower, 6.5 TFS pushrods (used), Sealed Power lifters, CAT shaft rockers, F-cam (used), 1972 351 dooe-c heads (of course, used), ROL head gaskets, ARP head bolts, RTV'd all bolts, Holley systemax 1 lower, Cartech upper, 48lb injectors, stock rails, new FPR (stock psi), 3 fuel pumps (inline/parellel), stock lines for the most part, Comp Cams double valve springs (used), Crane fireball, Accell cap/rotor/wires, Holley coil and megasquirt v2.2


Looking for any applicable opinions, thoughts, ideas and/or solutions for an unstable afr.

[my8950]

vacuum leaks, crappy sensor, sensor placement, even depends on which RTV you may have used.  I'd be willing to bet your calibration just needs more work. 

[vwdave]

Misfires will cause a A/F ratio to show lean spikes.

[goatnipples2002]

Sealing up the exhaust really helped a ton and yes my tuning skills sucks. I will stick to mechanical shit. Got a buddy that worked for Spectre so he will help me tune.