DD issues

[Snowman1000]

Hey Fella's been a while since ive been around been busy working out of town with a new job. Well long story short I'm having some issues with my daily driver. Its an 02 1500 GMC Sierra Z71 with a 5.3 its been a great truck until the last few weeks. It started about two months ago I had a random service engine light a bank 1 lean the guy at O Reilly's cleared it and said it was probably bad gas. Well fast forward to two/ three weeks ago. The light came back without any obvious problem same lean bank 1 or 2. Then it got cold and when it started getting cold it got worse it misses and doesn't want to idle when its in the negatives but straightens out once it warms up. I had the codes checked lean on bank 1&2 and random misfires.
I changed the plugs three weeks ago I tightened down the plastic air plentum boot and cleaned the mass airflow sensor with no change really.
Any ideas what could be giving me fits? I'm just trying to get an idea so I can get it care of on a weekend because I am out of town Monday through Friday.
Thanks for any help guys

 

[Stomis]

Since its affecting both banks you should be looking up stream of injectors/plugs and coils. Good starting point would be to hook up a good scanner and make sure things like the MAP, IAT, TPS, CTS etc are reading good. These things will affect fuel trim for both banks, IE there isnt a separate sensor for each bank and or cylinder.

If you had an injector, plug, or coil issue it would flag one bank or even specifically one cylinder. o2 sensors will flag one bank. In fact the only fuel related wear parts that will affect the entire engine is the fuel pressure regulator, fuel filter, and fuel pump. Another good thing to check would be that you have adequate fuel pressure, although your rough on cold start doesnt really lean me that way.

My stab in the dark is coolant temp sensor is reading funky when its cold and the parameters do not compute with the needed fuel trim for the given moment. The sensor can be totally dead when cold but work fine at operating temp.

 

[Snowman1000]

The fuel pump and alternator are new too. Ill try and find someone with a good scanner its all a little Greek to me.