Recently purchased 2004 Ranger Edge 3.0 single cab 200,000mi
I throwing check engine light. Runs fine.
Codes: p0174- fuel to lean cyl bank 2
P0506- idle air control system rpm lower than expected
P0455- Evap control system large leak detected
P0171- fuel to lean cyl bank 1

Any thoughts?

I thought PCV valve, but can't seem to find its location.

 

P0171 Lean on Bank 1, passenger side
P0174 Lean on Bank 2, drivers side

What is means is that the computer is opening the fuel injectors longer that it has calculated to get the O2 sensor to read .5 volts, balanced Oxygen level in exhaust

Since both banks are effected it is an upper intake air leak or lower fuel pressure

PCV Valve hose would be prime suspect, look here: http://repairguide.autozone.com/znet...3f8021b8b9.gif

The elbow was a common leak point

To tell if a vacuum leak is responsible you can do this test.
After engine is warmed up and idling
Unplug the 2 wire connector on IAC Valve
Valve will close and idle should drop down to 500rpm or engine may even stall, that is GOOD, it means no vacuum leaks

If idle stays the same then there is a leak

Picture of an IAC Valve here: http://www.explorerforum.com/photopo...re_low_res.jpg
Not a 3.0l but they all look the same

P0506 is an IAC Valve code but could also be caused by the vacuum leak or low fuel pressure, so fix the Lean codes and then see if it comes back

P0455 EVAP system leak
EVAP system sucks gasoline fumes from the gas tank
So gas tank MUST BE a sealed system when gas cap is on
When you start the engine the computer will open the EVAP Solenoid a bit to apply engine Vacuum to the gas tank, this creates a slight negative pressure in the tank so any gas fumes are sucked out and into the engine to be burned and not pollute the air.
Computer has a pressure sensor on the EVAP hose running back to the tank, if the tank can't hold pressure very long the it will set a code.
If it can't hold ANY pressure then it will set P0455- Evap control system large leak detected

And this could be your vacuum leak, if EVAP solenoid hose is off or broken then it would be a vacuum leak
This will be in the engine bay, but can't say what 2004 3.0l EVAP solenoid will look like
Maybe hit a parts store and have them pull one out so you can look at it, or go online and do the same.

EVAP code could also be filler hose from bed to tank is bad, or gas cap is not tight.
Any openings in the gas tank, so it is no longer sealed would cause that code

Most know the EVAP system but never knew what it was called
When you stop to fill up at gas station and you open the gas cap you would hear a "WHOOOOSH" as the gas cap seal was broken, that's caused by the EVAP systems negative pressure in the tank.
You probably haven't heard that since the code was set :)

 

Awesome! Great help!
With the Evap code, the guy I bought it from told me that if you fill the tank up and then try and sip in a few more pumps trying to round out that last dollar, the filler neck will leak.

Any thoughts on that?

 

Yes, filler neck needs to be replaced, thats why the code

And NEVER EVER EVER overfill gas tanks on vehicles 1995 and newer, NEVER EVER

First Click off, you are done, deal with it or budget for new charcoal canister and install of that part, minimum is $350 for the part, $1,500 installed is high but not outrageous

Back in the 1990's automakers moved the charcoal canisters, used to filter the EVAP air/fumes, from engine bay to back by the gas tanks, so if you overfill the gas tank gasoline will run out the EVAP air hose and into the canister which ruins the charcoal and clogs up the system.
So what?
Well that is also the vent for the gas tank, so while you drive fuel pump is pumping gas out of the tank, if EVAP system doesn't/can't balance the pressure in the tank while fuel goes out then you will end up with an "air lock" in the gas tank, fuel can't be pump out of the tank fast enough and you will feel the truck "running out of gas".
You can stop open the gas cap to equalize the pressure and drive on, or leave gas cap loose all the time
Neither is great solution
But can be avoided by NOT overfilling the tank

 

Found the pcv valve. Swapped it out. I'll go get the code cleared and check back.

 

Wouldn't be the valve, usually the hose for the valve is the problem

 

Interesting.. I Swapped out the valve.. didn't seem to help much. I tried the IAC test.. the motor didn't shut off..
Looking at the elbow for the PCV it seems to be in pretty good condition.. any other spots to look for the vacuum leak?

 

RPM didn't change at all?

That's the test, engine RPM should drop down when IAC Valve closes(unplugged from power), engine doesn't need to stall

Must be an Upper intake leak to effect Both Banks of a V6
With IAC valve unplugged, you can pull off 1 vacuum hose, from the upper intake, at a time, then plug that port with your finger to see if RPMs drop down.
If not reconnect hose and move to the next hose
If it drops then that hose or the device at the end of that hose has a leak.

Start with PCV Valve hose and the Power Brake booster hose, then move to smaller hoses

 

Ok, so I did some testing this evening.
Started the truck up and it rev'ed to like 2,000ish and then died.
started again and kept my foot on the gas around 1,000 rpm to make sure it wouldn't die. waited about a min. then it was fine.
Drove down the road a few miles with some stops and go's everything was fine.

Picture #1 (The one with all the circles) Red-IAC pulled the wire off with no response on the engines behalf (nothing happened, didn't die)
blue- (not sure what sensor) but pulled the wire off and nothing happened.
Green- pulled off big sucking noise and didn't die, but was headed there.
purple- pulled off- died
yellow- to the brakes- pulled off and died
white- PCV pulled off and died

Picture #2 (the one with the single circle)
This is the only other vacuum line that I could find.
It goes under the upper intake and the other end heads down to some weird plastic ball thing. I pulled it apart at section circled and engine did nothing but there was a clear suction on the other end heading to the intake...

Thought?

 

You have to put your finger over the port as soon as you pull off the hose or engine will have a SECOND vacuum leak, if that hose wasn't the leak, so engine may die


#2 sound promising, plug the port, Block the suction, and see if idle drops down

Ball thing is the Vacuum reservoir, stores vacuum for opening the vents in the cab, i.e. Defrost, Panel and Floor selections.
Do they work normally?

 

Gotcha!
Ill try that tomorrow.
I did put my finger over both ends of the 2nd pic. nothing happen to engine while it was opened or plugged.

Ill have to check on the opening and closing of the vents. but to my knowledge they all work. Will update when I check

 

New development.

The tighten fuel cap light came on and no matter how much I tighten it, it still stays on.

Could this be causing the codes?

 

There is no "tighten fuel cap" code, just FYI

There are EVAP codes where one of the suggested fixes is to make sure fuel cap is tight

EVAP is evaporative emissions system, it seals the gas tank after engine starts so gasoline fumes don't pollute the air.
When you drive around the gas sloshes back and forth in the tank so alot of fumes are produced.

The EVAP system uses engine vacuum to put a slight negative pressure in the gas tank, it then pulls any fumes out of the gas tank and they are sucked into the engine to be burned.
When you stop to fill up any vehicle now-a-days, you may have noticed a "whoooshing" sound when you start to remove gas cap, thats from the negative pressure in the gas tank created by the EVAP system
When you stop hearing it an EVAP code won't be far behind, lol.

EVAP has a pressure sensor, so when it apples the negative pressure to the gas tank, the pressure should hold, if it doesn't then there will be an EVAP code set
If gas cap was loose that would prevent gas tank from holding pressure, so it is one of the things to check, but not the ONLY thing

Most common issue is the Filler/Vent hoses getting cracks, the rubber gets old and cracks so gas tank can't hold pressure.

But post the EXACT code number, there are several EVAP codes

 

It was the tighten fuel cap light.

Looks like this

 

It's an EVAP code idiot light, have codes read at auto parts store to get the exact EVAP code number, it will usually be P0455, fuel tank air leak code

Check engine light(CEL) will come on over time if it isn't already on, it gives the driver a few days to check gas cap just in case that IS the only problem, but a code will be there regardless or that "gas cap" light wouldn't have come on