I have a ram1500 with a v8 5.9l and i just put heads and did the kegger mod. I have been trying to figure this out but cant. When i first start it up(when the engine is cold) it idles way lean and will continue when driving. But it i stab the throttle wot for just a second from then on its good. Until it cools down again. What do you think would cause this? I have done tps sensor, temp. Sensor, intake manifold temp sensor. I dont know. Anything will help. Thanks

 

Check Fuel pressure.

 

Stock heads? Was the plenum gasket still good? Maybe should replace o2 sensor also. And I'm just curious to know, how you know it's lean?

 

Why would it only do that when its cold. And go away? Wouldnt it be all the time?

 

There heads with bigger intake valves. I didnt the hughes fix. Its not leaking now. I have a air/fuel ratio gauge that i use for custom tuning

 

Not a slow responce O2 sensor.

It could be the intake manifold temp sensor, check resistance. I posted up the values in this section, search under me in here. Also I agree, a pre-cat O2 sensor could cause this issue.

 

I have tried two different intake manifold temp sensors. So i would be shocked if that was it. Ill try new o2sensors

 

Well i tried the pre cat sensor. And that didnt do it. Anything else?

 

And your using a wideband o2 with the gauge?

 

Ok, I was just confirming. Have you checked the ECT also?