What fuel grade are you using?

 

How would I know if it's too rich or lean code? Any easy way to check that with IID? Not a bad idea on the plugs -- Maybe I'll just order a set n' change them. They'd tell me if one cyl was running lean or rich, in theory. I know they've not been done in the past 20k miles.

93, every time. From Shell / Mobile / Sunoco generally.

Dave aka Ghan

 

The IID should say "P0173 Bank 2 too [X]" if I'm not mistaken. It always did on mine... Do you have the bluetooth version? OBD won't tell you if a single cylinder runs too rich/lean, just how that bank runs. It's an oxygen delta measured by the upstream O2 sensor, so there's no way for it to know which cylinder in that bank is out of trim. Beware the plugs on the V6 are absolutely buried, especially the rear-most ones... Not sure about the V8. According to my indie mechanic, Rover engines much prefer the classic Champion copper plugs, none of the new-fangled Iridium, Platinum, or tri-tipped plugs. Good news is they're dirt cheap. Get them at your local parts store so you can inspect them before buying. Look at each one and check for cracks in the ceramic. These things get dropped at parts stores all the time - then picked up and put back on the shelf. Ask me how I know. Get a good plug gapper, the wire-gauge type, not the coin type. Don't overtorque them.

You may want to try Houm_Wa's suggestion of a can of BG44K in a full tank before changing the plugs, as legend has it you can foul spark plugs with additives. That being said, don't run that tank empty before filling up to avoid running additive through new plugs. Run down to 1/4 tank, then fill all the way up and change them. This way at least you have the most foolproof method to make sure you have good, new spark plugs and a fresh fuel system cleaning with the Rover-recommended cleaner.

 

From the output of IID:
=-=-=-
Model L319 - LR3 2005
Vehicle scanned on Feb 23, 2019 1:03:29 PM
IIDControl 2.9.4.5 Android - IIDTool BT V3.0 B2624

Engine Petrol

P0173-00 (AA) Fuel trim (bank 2)

Ventilation
=-=-=-=-

I'll try a can of the BG44K and a fuel adaptions reset and see where that leaves me. Plugs after the first BG44K tank. ...couple of full tanks -- Talk to you guys in a couple months when I get through it. :P

Dave aka Ghan

 

FWIW, the LR Dealer advised me that the BG treatment that gets run through the fuel rail is known to foul plugs....but didn't say as much about the tank-additive. This was during a "Spa Day" in which I purchased all three BG products (the tank variant, the rail variant and the air induction variant) and they were good with doing 2 of 3 but advised to hold off on the fuel rail one until I am on the brink of changing plugs (again). Come to think of it I still have that can of product in my shed.

 

Just a quick update -- I used the IID tool to "reset engine adaptions" and cleared the code. I have put on over 100mi on the truck without the check engine light returning. Might have been that easy of a fix!

Here's to hoping! Just have to go hit emissions before it does!

Dave aka Ghan