Air/Fuel ratio at idle?

[98BLKGT]

What a/f ratio should a wideband read on a cold start at idle?

 

[millhouse]

Idle should be at 14.7:1.....although cold starts throw in enrichments to keep the engine running. As to what those enrichments are...I can't say. I would expect the wideband to read a bit richer at idle though (the colder, the more rich you will typically see to a certain extent).