i posted this over on ls1tech this morning. thought i would post it over here as well to see if you guys could help out.



wandering if anyone knows what is up with this commanded afr and the o2s? afr goes to 16, o2s flat line lean, then the afr goes to 13.6, o2s go rich then back to normal. i can give it 10-20% more throttle and the afr will come down to 14.6 or less and the o2s will start switching, but as soon as i back off the throttle its back to the 16 or 13.6 afr. it seems to happen after start-up (cold or warm) and a short normal drive of about 10 mins or so. then it happens. they all last about a minute or so. is this the evap? apologize for sqeezin the chart up, but wanted to get the whole cylce in.

 

not sure but I notice my 02s go to 0 when coasting up to a stop sign
maybe dfco?

 

that is really wierd I thought dfco at first but unless youve messed with the settings for when it kicks in your tps should eliminate that. your oscillations and trimming all stop and the thing is that its doing it through vairous tps, speed, load and even inj pw is changing I would tend to think its a problem with the 02's but then again both of them at the same time doesnt make sense. So maybe the software or hardware is dropping the signal somewhere along the line problem with hp tuners or your laptop. I would lean toward a problem in connection somewhere. I cant think of anything else I dont think the 02's have actually stopped oscillating and the pcm trimming.