Civic EG

So I've been experiencing a problem with my car; some times it runs normal air/fuel reads good between 12.1-13 and it idles fine, and then some times while driving the car just starts the go rich the air/fuel reads 11's and then as low as 10's and the car stalls at idle, and when i try to re-start the engine stutters and bogs. I have to turn off the car and switch the ignition on and off till the air/fuel builds up to 13's then the car starts normal and drives good, but sometimes the problem re-occurs while driving again....what could cause this? it very frustrating at times
any info on what could cause this or opinions would be greatly appreciated thanks.

for my build and parts list click the link : http://civic-eg.com/viewtopic.php?t=21353&start=45

I assume there is no check engine light?

I would start with looking at the o2 sensor. If the weather has changed drastically since you had the car tuned, it may need a re-tune. Sometimes people must run a separate tune in summer and another in winter.

Nope no check light, I live in the caribbean so the climate pretty much the same all year round, might be a drop in temp during November-December but not much to talk bout. But getting a re-tune sounds like a plan