Sorry, I posted this in my intro, and it should have gone here instead...my bad.
At any rate, I have codes po174, po171...lean on both banks. I have all but given up. I have replaced the IMT (sp?) o-rings, the intake gaskets, the plenum gaskets, have had the intake smoked (not at the dealer), replaced the fuel filter and stared at the engine for hours with and without carb cleaner in my hand. (Although I have now found out that with an electronic throttle, carb cleaner will not change the idle.) Oh, and changed the mass air flow sensor.
I even bought the lower breather hose, from the dealer, only to find the 06 does not have one. So I am really pleased with my dealer selling me this part and allowing me to spend 3 hours R&Ring the intake, again.
Any thoughts?

Minutes ago I checked the gas cap....it appears fine.

Again, thanks for all that have helped me over the years, even though you didn't know it.

Khris

 

Sorry (new to posting) its a 2006, 100K, 3.0.

Khris

 

As you have already diagnosed, P0174 is Bank 2 combustion too lean.

The possible causes are:

1. Engine misfire
2. Air intake leak between MAF Sensor and cylinder head
3. Fuel filter / system restriction
4. Fuel injector restriction
5. IP Sensor fault (low fuel pressure)
6. Low fuel pump output
7. HO2 Sensor(s) (2/1, 2/2) harness wiring condition fault
8. EFT Sensor fault (low fuel temperature)
9. MAF Sensor fault (low intake air flow)
10. Exhaust leak (before catalyst)
11. ECM receiving incorrect signal from one or more of the following components:
a) ECT Sensor
b) MAF Sensor
c) IAT Sensor
d) IP Sensor
e) EFT Sensor
f) TP Sensor

The same goes for P0171.

Graham

 

+1 to GGG - can't think of anything to add but maybe focus on O2 sensors...

 

Khris welcome to the forum.

Check this link out:

https://www.jaguarforums.com/forum/s...ics-faq-52720/

 

Can you get a lean code, and have a faulty O2, without an 02 code?

 

Yes, I have seen this, but I do not have the purge control can, or that vac line in red. Thanks though, I do appreciate any advice......or dealer it goes.

Khris

 

I'd get an OBD tool with live data.

Look at the freeze frame data in case it helps.

Also, check all the main sensors for plausibility at idle (easy) and if you can at the conditions in the freeze frames but at least look hard at that data. Be vigilent.

Watch the upstream O2s as you blip the throttle and again if you squirt a bit of propane into the air intake.

Make sure the downstream O2s are very different as they're not the same technology.

I think your car (being 06) has SAIR (which means extra air added after the engine into the exhaust) so you just about could have a problem there but as you have both banks lean it's far more likely to be earlier.

Always remember the car can only measure O2. It can't measure unburnt fuel, for example.

So it has to adjust fuel based on the O2 and what it sees the O2 sensors saying. It trusts the injectors etc to be nearly right and the O2 lets it see how to trim the fuelling. And so on.

Over here we measure tailpipe gases every year and that means it would be easy to pay for an extra test because that way you get far more than just O2 readings. May or may not be helpful

Here's the kind of thing modern cars do (as per CARB / EPA) OnBoardDiagnostics.com - Engine Basics

 

Check the EGR and it's tube communicating with the passenger side exhaust manifold. Though unlikely for an 06, the tube and vaccume lines rot out. Also check the brake booster hose where it attaches to the intake manifold. The smoke test should have uncovered the preceeding but are we sure the tech was efficient with this test?

 

As JAGV8 says you need some live data.
Short and long term fuel trims are going to help with diagnosis.
An EBay bluetooth dongle and the Torque app running on Android is a cheap and good OBD solution.

 

Brutal's in TX, isn't another tech? Close enough?

 

Motorcarman (Bob Gauff) is in Decatur, not a million miles away.

 

Bob knows the cars

(As does Brutal, but if Bob's fairly near...)

 

I reckon Bob is about 50 miles and Brutal close to 300.

 

Might I ask if the vehicle was throwing the codes prior to the running lean condition. I know silly question but.....

Were you doing spark plug replacement or something else then put it back together and it started throwing the lean codes?

 

Good question. No the codes were the reason for any work. I did do the plugs while trying to sort out the codes, however.

And to everyone else, thanks for the advice. I figure I might as well have a better code reader, so that is my next step.

Thanks again,
Khris

 

Hmmm I wonder if this is what you are refering too(?). This was definetly added to the 2006 MYs.

 

Er, I don't know what it looks like! Just read it was added and that plus knowing what it does isn't actually much use

I don't think it's likely to be the cause of the trouble.

 

Khriss, if you've changed all that already, and still got 'em....I'd take it to Bob(Motorcarman); well worth your drive.

FWIW, Swapping MAF's between my 03 and 05 cured the same problem on the 05.....for a year, then the 03 (with original 05 MAF aboard) started popping 171/1474. Swapped 'em back and ordered a new MAF. In the 3 weeks or so between when I put the 05's original MAF back on and when I got 'round to installing the replacement, no codes.

 

Dang! aholbro, are all those machines in your garage registered and insured?