On my 99 v10 I had a code pop up and tell me that bank 1 is running lean I replaced my fuel filter cleaned my MAF sensor Checked my vacuum lines but I dont think i checked them all is there a diagram for the vacuume lines so that I know that I checked them all or is there anything else I do need to check thank.

 

The vacuum line diagram should be under your hood.

 

Check the rubber elbow in the PCV plumbing where it connects to the throttle body. that's the usual culprit.

 

I have already replaced it But I checked it again still good and I was able to check them all out there good I wouldnt think it would be the fuel pump just cause if its done it will simply stop working.

 

Fuel pumps can start to not flow enough ... also, fuel regulators can stick or get clogged with crud.

Check the fuel pressure. Should be 28-30 when idling, 38-40 with key on and engine NOT running. Cycle the key between off and on (to the point when the dash lights all come on) a few times and check the pressure.

 

A fuel problem wouldn't be isolated to bank 1.
Check the PCV on that side, as indicated above the 90 degree under the throttle body is prone to failure.
Also, the boot on the TB can crack...

 

I had a similar issue on a 98 F150 5.4 and the o2 sensor was actually bad. Sometime they don't throw the o2 code.

 

I just replaced both O2 sensors still no change

 

Hmm ok. I would check into fuel pressure at each rail.

 

O2 Sensors do not cause "lean" readings, they report them.

If this is an OBD1 calibration, it doesn't report fault codes for bank 2.

 

Again, the most likely cause is a vac leak. Some people use propane to test, but I've never had a lot of luck... Carb cleaner can work too... You're looking for anything that changes how the engine runs when spraying on or near vac hoses.

In extreme cases (or use with turbos) I've built PVC / Silicone deals that attach to the intake and pressurize them to a few psi to find leaks.

 

That's interesting...

 

well after replacing O2 sensors replacing vacuum hoses and also fule filter and air filter finally found the little culprit the little gasket pluggig up the hole where the MAF Sensor wires go through that popped out that caused a big enough vaccume Leak. been driving around after I cleared the codes its been 60 miles and no code pop up. Thanks everyone for the help. This is my first v10 and I bought it with 200k miles I already had the tranny rebuilt and I just installed a summit racing radiator new hoses and thermostat water pump and clutch fan. Is there anything else I should probably keep a lookout for and or just replace.

 

yeah, that little plug is a pain... thanks for reporting back