2001 ford ranger bank 2 lean

[joshuakaesekamp]

3.0 v6 has code bank 2 lean runs fine no i high or low idle just replaced fuel pump because of slow start witch is now fixed. just wondering if anyone has any ideas or what could casue it. ive went over most vacum lines and they seem to all be fine and bolth exhaust gaskets are new if any one has any ideas or ways of trouble shooting it would be much appreciated thank you

 

[RonD]

Lean code on just one side of the engine is usually not a vacuum leak unless its a lower intake gasket leak
Anything in upper intake or MAF sensor would effect BOTH sides of a V6 engine

O2 sensors can only "see" Oxygen, not fuel, so "lean" means too much oxygen in the exhaust on that bank
O2 sensors only last 150k miles or 12 years then they start to show lean, they run out of chemicals

Lean code means computer is having to opening injectors on that side of the engine 15+% longer than it calculated and its consistently over 15% longer or it won't set the code
So could be a clogged injector on that side, try running some Seafoam, or similar injector cleaner in the gas tank

Misfires don't burn up any oxygen so that oxygen is dumped into exhaust manifold, so Lean
But you said it runs smooth, no misfires

Exhaust manifold can suck in oxygen if gasket is bad, so Lean, but you say they are new

Long shot is failing Cat converter used on that bank, if it has separate converters, they can break up inside and slow the exit of exhaust, which causes O2 to show lean

If MPG has gone down a bit then its most likely a "false lean", so computer is adding more fuel than needed, which would be O2 sensor, exhaust manifold leak, or clogged exhaust

 

[joshuakaesekamp]

thanks for your reply is there a way to test the o2 sensors to know if there broken or do you just have to replace them to find out if there broken. this truck has 181000 miles on it.

 

[RonD]

At that many miles I would replace both upstream O2s, just because MPG will improve for sure
At the cost of O2s they more than pay for themselves in fuel savings over the next 10 years

But yes you can swap the upstream O2s around, and if lean code moves to the other side then its that O2 that's failing
But the work to do that is usually more hassle than just replacing both, lol, especially at 180+k miles

 

[joshuakaesekamp]

okay thank you ill look into replacing thoes

 

[joshuakaesekamp]

so i replaced the upper intake gasket and both o2 sensors and that fixed the check engine light thank you for your help

 

[RonD]

Good stuff

Thanks for the update and THE FIX