Rough Idle when cold

Hello, I am new to this list, so bear with me... I have a 2002 silverado with 50k miles on it. Just recently it has started to idle really rough when I first start it, and after about 5 minutes of driving, maybe when it goes into closed loop, the check engine light comes on and gives me two codes Engine lean Bank one, and Engine lean Bank 2. I checked the fuel pressure after it quit running like crap, and it is right on 50psi, but I haven't checked it cold. It also seems like it is not getting as good of fuel milage as I used to. Anybody have any ideas?????
Thanks in advance,
Randy

fuel regulator. driver side under hood by firewall.

Welcome to the forum!!!! :smokin:

Hello, I am new to this list, so bear with me... I have a 2002 silverado with 50k miles on it. Just recently it has started to idle really rough when I first start it, and after about 5 minutes of driving, maybe when it goes into closed loop, the check engine light comes on and gives me two codes Engine lean Bank one, and Engine lean Bank 2. I checked the fuel pressure after it quit running like crap, and it is right on 50psi, but I haven't checked it cold. It also seems like it is not getting as good of fuel milage as I used to. Anybody have any ideas?????
Thanks in advance,
Randy

Your problem sounds exactly like the one my son had, start and cold idle was lousy, 50 psi fuel pressure, which I thought was enough. Wrong, the spec calls for 55-62 psi and believe me, the shortage of 5-7 psi was enough to cause it to run crappy. We changed the fuel pump this weekend and it fixed the problem, and the shitty gage that GM put in originally, it never worked on it, we bought it with 60,000 miles. SO that is probably your problem as well, we got a fuel pump from O'Reilly for about $300, I imagine the dealer would charge upwards of one grand for the job. It wasn't too bad, you have to drop the tank or take off the bed. We dropped the tank, but make sure you empty it first, it's a beast to do on your back. You'll need some small floor jacks or similar to put it back up. Good luck.

Your problem sounds exactly like the one my son had, start and cold idle was lousy, 50 psi fuel pressure, which I thought was enough. Wrong, the spec calls for 55-62 psi and believe me, the shortage of 5-7 psi was enough to cause it to run crappy. We changed the fuel pump this weekend and it fixed the problem, and the shitty gage that GM put in originally, it never worked on it, we bought it with 60,000 miles. SO that is probably your problem as well, we got a fuel pump from O'Reilly for about $300, I imagine the dealer would charge upwards of one grand for the job. It wasn't too bad, you have to drop the tank or take off the bed. We dropped the tank, but make sure you empty it first, it's a beast to do on your back. You'll need some small floor jacks or similar to put it back up. Good luck.

PS

My son's truck is a 2000 Silverado with a 5.3 liter V-8, fuel pressure is supposed to be 55-62 psi at the Shrader valve.

I appreciate everyone's help. I am going to take the truck to the dealer and have them work on it since it is still under warranty. It makes sense what everyone is saying especially because of when the ses light comes on. It only comes on when it goes into closed loop. So since it is on the edge of having enough gas at this time, any colder won't allow the o2 sensors to tell it that it doesn't have enough fuel.
Anyway, thanks again.
Randy