Got 2 engine ODB code error...

[insistent]

Hello, i have a ranger XLT 2000 4x4, and i have 2 OBD code error.

I have a ultragauge and it can show my code error, i had the P0455 for a while in the pending page, wich is evap system or something, but i ignored it because there was no check engine, but today a check engine popped up, this one is P0171, wich is lean status.

I know that there can be many cause for each code, but i was wondering what would be the most common reasons for these truck, or what sensor is more apt to fail? Im at 202 000Km.

Thanks

 

[adsm08]

P0455, Gross leak or no flow. P0171, bank 1 lean. I am going to guess you have a 4.0 SOHC, since you didn't tell us.

If so, take the appearnace cover off (the stupid piece of plastic that says "4.0 SOHC") and check the rubber elbow going into the side of the throttle body. They have a tendancy to tear, and that will give you a lean code.

 

[insistent]

Its a OHV

By the way, the motor when warm, will idle at around 800-900rpm, it has to be lower right? Must be really a vacuum leak then?

 

[RonD]

Idle is too high so my guess is you have a vacuum leak.

With engine warmed up and idling unplug the wires on the IAC(idle air control) valve, upper intake front.
Idle should drop down to 500rpms or so, engine may stall, either is a good sign of no vacuum leak.
If idle stays up then start unplugging vacuum hoses on intake and plug port with your finger, when idle drops you found the hose/system with the leak, my guess would be EVAP system.

Computers target idle warm is 700-750 for manual trans, and 750-800 for automatic.

EVAP system has a vacuum control valve that the computer opens when engine is running, this uses engine vacuum to suck air from gas tank so fumes are sucked into engine not released into the air.
This air from the gas tank passes thru a charcoal filter canister.
There is also a pressure sensor on the system which is what activated the P0455 code.
If you leave the gas cap off you will get that code because system can not hold negative pressure.
If any EVAP vacuum hose is cracked/leaking you get the code, or if canister is leaking.

Since you are now getting Lean condition code my guess is that the EVAP leak is now large enough to effect air/fuel mix with too much air.


Bank 1 is the passenger side of the engine, so cylinders 1, 2 and 3, a misfire on these cylinders will also cause lean code P0171.
Slight missing won't cause a misfire code but can cause lean code, do you have a slightly rough idle or issues when driving?
If you don't have a vacuum leak you could have a dirty injector or bad spark plug.
Pull the spark plugs and have a look at them, re-gap them if they look OK.