Promaro

Does anyone know why it could be doing this? Changed the filter, just put a new pump on it. While I give it gas it is fine but if I let off or let it idle it will become very lean, sometimes even when i let off it will be extremely rich for a few seconds then dip back off, im scared to drive it like this.

Ryans99ls1

iTrader: (16)

to be honest, if its accurate under driving conditions i wouldnt sweat it. My tuner was watching my wideband and his during tuning and he said theyre both accurate under load conditions but at idle mine is pretty far off from his and his is proven to be accurate. I have an AEM too..

i suggest seeing if you can get on a dyno real quick and use theirs to compare.

vmapper

iTrader: (8)

One can guess..
you removed the battery and zeroed all the Trims ?
This exposes a 'crap' tune if tuned at all for the Base idle airflow (RAF)... you dont mention if you removed the battery or not though...

Promaro

Thanks for the info just worried me alittle when i saw that my buddys stays at optima during idle.

Promaro

Havent removed the battery, ill try that.

Monte4ever

iTrader: (2)

Did it fix your problem?

Promaro

No it didnt change anything. Could it be the tune? Im putting a 6.0 in it sometime this fall/winter so its not like its an emergency just would like to know why it does this.

black98ws6ta

iTrader: (77)

Car have full exhaust? No exhaust leaks? Does it have 02 sensors, closed loop tune? Being lean at idle is not going to hurt anything, but obviously 14.7 is ideal.

The Alchemist

iTrader: (19)

Do you have programming software? Are you relying strictly on the AEM gauge to see afr or are you data logging it? If you have data logging software, log not only your wideband O2, but also your narrow band O2's as well and compare them. Your factory narrow band O2's are extremely accurate in the 14.7 +/- 0.5 range so you should be able to see if you really are lean or if it's just your wideband acting up.

Also, check in your tune if you have decel fuel cutoff activated. Going lean on full decel isn't bad or harmful to your motor. There's no load on the motor, so there's no need to pump fuel through it.

pwrtrip75

iTrader: (8)

What injectors? What is your injector pulse at idle? Fuel pressure the same as it was? My setup has some billet atomizer injectors, very finicky to get to idle, fuel pressure cant be too high and the wont go below a certain pulse. So if i lean my idle out more than 13ish:1 they start shutting off and I get a super lean idle. If your fuel pressure is too high in order to get the right idle mixture the injectors might not be able to pulse that low....? Could be fuel pressure related if you just changed the pump..... My opinion.

FasTimeSS

iTrader: (47)

Itss ur tune? And there is nothin wrong with being that lean as long as it isnt poppping

The Alchemist

iTrader: (19)

Honestly, you haven't given enough information for any of us to make any kind of informed opinions. What injectors, what your fuel system consists of, what type of tune your running (open loop, closed loop, etc).