Put a new cam in an LS2 (LS3 heads, intake, TB. LS9 injectors). Long tube headers with wideband in the collector. Cam is TSP stage 4, F35 I think they call it - 235/248 .649/.615 on a 111 lsa. Idle MAP is about 70 kpa. MAP stays pretty solid 69-71. The commanded idle is 800 RPM. Timing is 15* but changing it to 18*, or more, doesn't affect much until idle eventually becomes unstable.

Idle fueling is being weird - I think it might be the injector timing?

At idle, I'm seeing 12.6 and it likes it. Sometimes it is hard to start when warm (needs pedal input sometimes), but that's a different issue I think. Timing is bouncing all over the place to hold 800 rpm's, say +-10*. If I move fueling to 14.7 it still seems to idle about the same but it needs lots of fueling removed to get there, say 32% (~60 to ~45 on VE). Logging also wants me to remove ~32% all the way through about 3800 RPMs. However, if I do this and move the fuel curve, then I start getting a shitty pedal off idle.

I've tried moving the injector timing all over the place, thinking there is raw fuel in the exhaust causing the lower afr, but I don't see much difference on the wideband.

Pulled #1 plug and it shows a little soot on the strap and threads, but porcelain is blackish/tan as far into the plug as I can see. So slightly rich idle?

Header temps are 400-450* at idle.

Thoughts?