5.0 banks 1 and 2 running lean

[audiodude332001]

Have a 2000 with a 5.0. Running really rough and codes say running lean on both banks. Yesterday morning I started it and I got the lean codes and rough idle.cleared the codes and ran fine. Drove 250 miles and no problems. Started this morning and same thing, drove 8 miles and it will hardly run. Keeps wanting to stall but doesn't. Cleared codes and running like crap but isn't throwing any codes now. Any ideas???

 

[Turdle]

CHeck the PCV hose grommet, they get loose and let the pcv valve slip out. it is in the middle of the intake manifold, at the very rear. It's kind of hard to get to. If this checks out ok, then folow that large hose system back up under the upper plennum. Some v8's have a vacuum t with a plug on one of the legs, this may have popped off, or, a hose was popped off. You may find a vacuum leak in a broken hose upon inspection.

One you verify no leaks, Check the MAf sensor is working correctly, and then look at the fuel pressure--

 

[audiodude332001]

Alright. Came out to the truck this morning, started it up and drove to work. Running just great. Haven't done anything to it since my first post. What the crap is going on?

 

[Joe Dirt]

Did you check what Jon suggested? The valve, hose, or cap can be loose. It can move around, and move enough to lay in place sometimes.

 

[Stefanlg55]

ive has the same problem on my 5.0 just follow the steps.

1. Check the small plastic vacuum line that comes out under the blower motor on the passenger side and leads to a plastic bulb towards the front of the wheel well.
(This line will control HVAC controls inside the Vehicle)

2. There is another line coming off the plastic bulb that cuts in front of the lower intake manifold and connects into the upper front half of the upper intake manifold. Its connected using a 2 into 1 fitting.
(This will be your Bank 1 and bank 2 lean condition)

3. Now follow the other line that is connected into the upper intake manifold and it runs under the battery stand i believe it connects into the Vapor Canister Solenoid.
(This will give you a small/larg EVAP leak)

You need to check these line for Cracks. They are hard to fine and tend to break often so be careful not to bend them much. I decided to change all my out when to autozone and got like 12ft of rubber vacuum line.

 

[audiodude332001]

Thanks everyone. Checked all of your suggestions and didn't find anything wrong. No check engine light since Mon and the trucks running great. Weird. Driving it from Eau claire to appleton tomorrow. Guess we will see how it goes.